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Gil-Fernández A, Ribagorda M, Martín-Ruiz M, López-Jiménez P, Laguna T, Gómez R, Parra MT, Viera A, Veyrunes F, Page J. Meiotic Behavior of Achiasmate Sex Chromosomes in the African Pygmy Mouse Mus mattheyi Offers New Insights into the Evolution of Sex Chromosome Pairing and Segregation in Mammals. Genes (Basel) 2021; 12:1434. [PMID: 34573416 PMCID: PMC8471055 DOI: 10.3390/genes12091434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
X and Y chromosomes in mammals are different in size and gene content due to an evolutionary process of differentiation and degeneration of the Y chromosome. Nevertheless, these chromosomes usually share a small region of homology, the pseudoautosomal region (PAR), which allows them to perform a partial synapsis and undergo reciprocal recombination during meiosis, which ensures their segregation. However, in some mammalian species the PAR has been lost, which challenges the pairing and segregation of sex chromosomes in meiosis. The African pygmy mouse Mus mattheyi shows completely differentiated sex chromosomes, representing an uncommon evolutionary situation among mouse species. We have performed a detailed analysis of the location of proteins involved in synaptonemal complex assembly (SYCP3), recombination (RPA, RAD51 and MLH1) and sex chromosome inactivation (γH2AX) in this species. We found that neither synapsis nor chiasmata are found between sex chromosomes and their pairing is notably delayed compared to autosomes. Interestingly, the Y chromosome only incorporates RPA and RAD51 in a reduced fraction of spermatocytes, indicating a particular DNA repair dynamic on this chromosome. The analysis of segregation revealed that sex chromosomes are associated until metaphase-I just by a chromatin contact. Unexpectedly, both sex chromosomes remain labelled with γH2AX during first meiotic division. This chromatin contact is probably enough to maintain sex chromosome association up to anaphase-I and, therefore, could be relevant to ensure their reductional segregation. The results presented suggest that the regulation of both DNA repair and epigenetic modifications in the sex chromosomes can have a great impact on the divergence of sex chromosomes and their proper transmission, widening our understanding on the relationship between meiosis and the evolution of sex chromosomes in mammals.
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Affiliation(s)
- Ana Gil-Fernández
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Marta Ribagorda
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Marta Martín-Ruiz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Pablo López-Jiménez
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Tamara Laguna
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Rocío Gómez
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - María Teresa Parra
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Alberto Viera
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Frederic Veyrunes
- Institut des Sciences de l’Evolution, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), 34090 Montpellier, France;
| | - Jesús Page
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
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Xu Y, Qiao H. A Hypothesis: Linking Phase Separation to Meiotic Sex Chromosome Inactivation and Sex-Body Formation. Front Cell Dev Biol 2021; 9:674203. [PMID: 34485277 PMCID: PMC8415632 DOI: 10.3389/fcell.2021.674203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 07/22/2021] [Indexed: 01/12/2023] Open
Abstract
During meiotic prophase I, X and Y chromosomes in mammalian spermatocytes only stably pair at a small homologous region called the pseudoautosomal region (PAR). However, the rest of the sex chromosomes remain largely unsynapsed. The extensive asynapsis triggers transcriptional silencing - meiotic sex chromosome inactivation (MSCI). Along with MSCI, a special nuclear territory, sex body or XY body, forms. In the early steps of MSCI, DNA damage response (DDR) factors, such as BRCA1, ATR, and γH2AX, function as sensors and effectors of the silencing signals. Downstream canonical repressive histone modifications, including methylation, acetylation, ubiquitylation, and SUMOylation, are responsible for the transcriptional repression of the sex chromosomes. Nevertheless, mechanisms of the sex-body formation remain unclear. Liquid-liquid phase separation (LLPS) may drive the formation of several chromatin subcompartments, such as pericentric heterochromatin, nucleoli, inactive X chromosomes. Although several proteins involved in phase separation are found in the sex bodies, when and whether these proteins exert functions in the sex-body formation and MSCI is still unknown. Here, we reviewed recent publications on the mechanisms of MSCI and LLPS, pointed out the potential link between LLPS and the formation of sex bodies, and discussed its implications for future research.
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Affiliation(s)
| | - Huanyu Qiao
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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3
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McNicoll F, Kühnel A, Biswas U, Hempel K, Whelan G, Eichele G, Jessberger R. Meiotic sex chromosome cohesion and autosomal synapsis are supported by Esco2. Life Sci Alliance 2020; 3:e201900564. [PMID: 32051254 PMCID: PMC7025286 DOI: 10.26508/lsa.201900564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/25/2022] Open
Abstract
In mitotic cells, establishment of sister chromatid cohesion requires acetylation of the cohesin subunit SMC3 (acSMC3) by ESCO1 and/or ESCO2. Meiotic cohesin plays additional but poorly understood roles in the formation of chromosome axial elements (AEs) and synaptonemal complexes. Here, we show that levels of ESCO2, acSMC3, and the pro-cohesion factor sororin increase on meiotic chromosomes as homologs synapse. These proteins are less abundant on the largely unsynapsed sex chromosomes, whose sister chromatid cohesion appears weaker throughout the meiotic prophase. Using three distinct conditional Esco2 knockout mouse strains, we demonstrate that ESCO2 is essential for male gametogenesis. Partial depletion of ESCO2 in prophase I spermatocytes delays chromosome synapsis and further weakens cohesion along sex chromosomes, which show extensive separation of AEs into single chromatids. Unsynapsed regions of autosomes are associated with the sex chromatin and also display split AEs. This study provides the first evidence for a specific role of ESCO2 in mammalian meiosis, identifies a particular ESCO2 dependence of sex chromosome cohesion and suggests support of autosomal synapsis by acSMC3-stabilized cohesion.
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Affiliation(s)
- François McNicoll
- Institute of Physiological Chemistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Anne Kühnel
- Institute of Physiological Chemistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Uddipta Biswas
- Institute of Physiological Chemistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Kai Hempel
- Institute of Physiological Chemistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Gabriela Whelan
- Department of Genes and Behaviour, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Gregor Eichele
- Department of Genes and Behaviour, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Rolf Jessberger
- Institute of Physiological Chemistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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4
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Nucleolus structural integrity during the first meiotic prophase in rat spermatocytes. Exp Cell Res 2019; 383:111587. [PMID: 31454492 DOI: 10.1016/j.yexcr.2019.111587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 12/19/2022]
Abstract
A typical nucleolus structure is shaped by three components. A meshwork of fine fibers forming the fibrillar center (FC) is surrounded by densely packed fibers forming the dense fibrillar component (DFC). Meanwhile, wrapping the FC and DFC is the granular component (GC). During the mitotic prophase, the nucleolus undergoes disassembling of its components. On the contrary, throughout the first meiotic prophase that occurs in the cells of the germ line, small nucleoli are assembled into one nucleolus by the end of the prophase. These nucleoli are transcriptionally active, suggesting that they are fully functional. Electron microscopy analysis has suggested that these nucleoli display their three main components but a typical organization has not been observed. Here, by immunolabeling and electron microscopy, we show that the nucleolus has its three main components. The GC is interlaced with the DFC and is not as well defined as previously thought during leptotene and zygotene stage.
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Abstract
The evolution of heteromorphic sex chromosomes has occurred independently many times in different lineages. The differentiation of sex chromosomes leads to dramatic changes in sequence composition and function and guides the evolutionary trajectory and utilization of genes in pivotal sex determination and reproduction roles. In addition, meiotic recombination and pairing mechanisms are key in orchestrating the resultant impact, retention and maintenance of heteromorphic sex chromosomes, as the resulting exposure of unpaired DNA at meiosis triggers ancient repair and checkpoint pathways. In this review, we summarize the different ways in which sex chromosome systems are organized at meiosis, how pairing is affected, and differences in unpaired DNA responses. We hypothesize that lineage specific differences in meiotic organization is not only a consequence of sex chromosome evolution, but that the establishment of epigenetic changes on sex chromosomes contributes toward their evolutionary conservation.
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Affiliation(s)
- Tasman Daish
- Comparative Genome Biology Laboratory, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Frank Grützner
- Comparative Genome Biology Laboratory, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia.
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6
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Page J, de la Fuente R, Manterola M, Parra MT, Viera A, Berríos S, Fernández-Donoso R, Rufas JS. Inactivation or non-reactivation: what accounts better for the silence of sex chromosomes during mammalian male meiosis? Chromosoma 2012; 121:307-26. [PMID: 22366883 DOI: 10.1007/s00412-012-0364-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 12/28/2022]
Abstract
During the first meiotic prophase in male mammals, sex chromosomes undergo a program of transcriptional silencing called meiotic sex chromosome inactivation (MSCI). MSCI is triggered by accumulation of proteins like BRCA1, ATR, and γH2AX on unsynapsed chromosomes, followed by local changes on the sex chromatin, including histone modifications, incorporation of specific histone variants, non-histone proteins, and RNAs. It is generally thought that MSCI represents the transition of unsynapsed chromatin from a transcriptionally active state to a repressed state. However, transcription is generally low in the whole nucleus during the early stages of the first meiotic prophase, when markers of MSCI first appear, and is then reactivated globally during pachytene. Thus, an alternative possibility is that MSCI represents the targeted maintenance and/or reinforcement of a prior repressed state, i.e., a failure to reactivate. Here, we present an analysis of the temporal and spatial appearance of transcriptional and MSCI markers, as well as chromatin modifications related to transcriptional regulation. We show that levels of RNA pol II and histone H3 acetylated at lysine 9 (H3K9ac) are low during leptotene, zygotene, and early pachytene, but increase strongly in mid-pachytene, indicating that reactivation occurs with some delay after synapsis. However, while transcription markers appear abundantly on the autosomes at mid-pachytene, they are not directed to the sex chromosomes. Interestingly, we found that chromatin modifications related to transcriptional silencing and/or MSCI, namely, histone H3 trimethylated at lysine 9 (H3K9me3), histone H3 monomethylated at lysine 4 (H3K4me1), γH2AX, SUMO1, and XMR, appear on the sex chromosomes before autosomes become reactivated. These results suggest that the onset of MSCI during late zygotene and early pachytene may prevent sex chromosome reactivation during mid-pachytene instead of promoting inactivation de novo. Additionally, we found temporal differences between the X and Y chromosomes in the recruitment of DNA repair and MSCI markers, indicating a differential regulation of these processes. We propose that many of the meiotic defects attributed to failure to silence sex chromosomes could be interpreted as a more general process of transcriptional misregulation that occurs under certain pathological circumstances in zygotene and early pachytene.
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Affiliation(s)
- Jesús Page
- Unidad de Biología Celular, Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain.
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Pan Z, Yang Q, Ye N, Wang L, Li J, Yu D, Cooke HJ, Shi Q. Complex relationship between meiotic recombination frequency and autosomal synaptonemal complex length per cell in normal human males. Am J Med Genet A 2012; 158A:581-7. [DOI: 10.1002/ajmg.a.35222] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 12/07/2011] [Indexed: 01/26/2023]
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Hultén M, Solari AJ, Skakkebaek NE. Abnormal synaptonemal complex in an oligochiasmatic man with spermatogenic arrest. Hereditas 2009; 78:105-16. [PMID: 4448692 DOI: 10.1111/j.1601-5223.1974.tb01433.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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9
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Franco MJ, Sciurano RB, Solari AJ. Protein immunolocalization supports the presence of identical mechanisms of XY body formation in eutherians and marsupials. Chromosome Res 2007; 15:815-24. [PMID: 17846907 DOI: 10.1007/s10577-007-1165-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 07/11/2007] [Accepted: 07/11/2007] [Indexed: 10/22/2022]
Abstract
The meiotic sex chromosomes of the American marsupials Monodelphis dimidiata and Didelphis albiventris were studied with electron microscopy (EM) and with immunofluorescence localization of meiotic proteins SYCP1 and SYCP3, and proteins essential for meiotic sex chromosome inactivation (MSCI), gamma-H2AX and BRCA1. The chromatin of the non-synaptic X and Y chromosomes contains gamma-H2AX, first as foci and then as homogeneous staining at late stages. The thick and split X and Y axes are labelled with BRCA1 except at one terminus. The bulgings of the axes contain SYCP1 as well as the inner side of the dense plate. The evenly spaced and highly packed chromatin fibres of the conjoined XY body in these species have the same behaviour and the same components (gamma-H2AX in the chromatin, BRCA1 in the axes) as in the XY body of eutherian species. These observations and recent data from the literature suggest that XY body formation is ancestral to the metatherian-eutherian divergence.
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Affiliation(s)
- M J Franco
- CIR, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Buenos Aires, PC C1121ABG, Argentina
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10
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Morales A, Mohamed F, Cavicchia JC. Apoptosis and blood–testis barrier during the first spermatogenic wave in the pubertal rat. Anat Rec (Hoboken) 2007; 290:206-14. [PMID: 17441213 DOI: 10.1002/ar.20417] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This research explores the initial assembly of the blood-testis barrier (BTB) during puberty, when a massive physiological apoptosis in the first spermatogenic wave takes place. Fragments of testis from 14- to 20-day-old rats were studied by conventional transmission electron microscopic techniques. Lanthanum hydroxide was used as an intercellular tracer. Light microscopy was used to confirm apoptotic death when paraffin-embedded sections were studied by TUNEL analysis. When the seminiferous cords reached the zygotene-pachytene spermatocyte level, they exhibited abundant apoptotic figures, whereas the remaining segments showed sporadic apoptosis. We found a BTB not yet assembled in the cords with zygotene-pachytene spermatocytes and abundant apoptosis. The observed apoptosis frequency diminished drastically when BTB was organized, as confirmed by the use of the tracer. Our conclusion is that the massive apoptosis found in the zygotene-pachytene spermatocytes between days 14 and 20 coincides with an open BTB. The absence of BTB could be one of the factors causing massive apoptosis of zygotene-pachytene spermatocytes, at least within the time span analyzed. The zygotene-pachytene spermatocytes are left exposed in an open environment instead of being isolated in the adluminal compartment to which they are destined.
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Affiliation(s)
- Alfonsina Morales
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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11
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Page J, de la Fuente R, Gómez R, Calvente A, Viera A, Parra MT, Santos JL, Berríos S, Fernández-Donoso R, Suja JA, Rufas JS. Sex chromosomes, synapsis, and cohesins: a complex affair. Chromosoma 2006; 115:250-9. [PMID: 16544151 DOI: 10.1007/s00412-006-0059-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 02/10/2006] [Accepted: 02/10/2006] [Indexed: 10/24/2022]
Abstract
During first meiotic prophase, homologous chromosomes are held together by the synaptonemal complex, a tripartite proteinaceous structure that extends along the entire length of meiotic bivalents. While this feature is applicable for autosomes, sex chromosomes often escape from this rule. Many species present sex chromosomes that differ between them in their morphology, length, and gene content. Moreover, in some species, sex chromosomes appear in a single dose in one of the sexes. In all of these cases, the behavior of sex chromosomes during meiosis is conspicuously affected, and this includes the assembly and dynamics of the synaptonemal complex. We review in this study the structure of the synaptonemal complex in the sex chromosomes of three groups of organisms, namely: mammals, orthopterans, and hemipterans, which present different patterns of sex chromosome structure and behavior. Of special interest is the analysis of the organization of the axial/lateral elements of the synaptonemal complex in relation to other axial structures organized along meiotic chromosomes, mainly the cohesin axis. The differences found in the behavior of both axial structures reveal that while the organization of a cohesin axis along sex chromosomes is a conserved feature in most organisms and it shows very little morphological variations, the axial/lateral elements of the synaptonemal complex present a wide range of structural modifications on these chromosomes.
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Affiliation(s)
- Jesús Page
- Departamento de Biología, Edificio de Ciencias Biológicas, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain.
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12
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Escalier D, Garchon HJ. XMR, a dual location protein in the XY pair and in its associated nucleolus in mouse spermatocytes. Mol Reprod Dev 2005; 72:105-12. [PMID: 15818601 DOI: 10.1002/mrd.20268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Xlr and Xmr are sex-specific genes which are expressed during the meiotic prophase I in the mouse. In spermatocytes, XMR concentrates on the asynapsed regions of the XY chromosomes, suggesting that XMR plays a role in sex chromosome condensation and silencing. The present study shows that in the mouse, XMR also concentrates in the nucleolus which is closely associated with the XY chromosome pair. In this species, the formation of a large fibrillo-granular nucleolus signals the activation of the ribosomal genes, but release of pre-ribosomal particles is inhibited. Using laser confocal microscopy we characterized the distribution of XMR in the XY body relative to the XY chromatin and the nucleolus. Immunoelectron microscopy showed that XMR concentrates in the fibrillo-granular component and the granular component (GC) of the nucleolus. In (T[X;16]16H) mouse spermatocytes, the nucleolus displays little or no activity and does not associate with the XY pair. XMR concentrated only on the XY chromosomes in (T[X;16]16H) mouse spermatocytes. These data suggest that XMR could play a role both in the XY pair and the nucleolus associated to the sex chromosomes.
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Affiliation(s)
- Denise Escalier
- Laboratoire d'Histologie Fonctionnelle et Moléculaire, Université Paris 5, Paris, France.
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13
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Metzler-Guillemain C, Usson Y, Mignon C, Depetris D, Dubreuil G, Guichaoua MR, Mattei MG. Organization of the X and Y chromosomes in human, chimpanzee and mouse pachytene nuclei using molecular cytogenetics and three-dimensional confocal analyses. Chromosome Res 2001; 8:571-84. [PMID: 11117353 DOI: 10.1023/a:1009277722579] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We used multicolour fluorescence in-situ hybridization on air-dried pachytene nuclei to analyse the structural and functional domains of the sex vesicle (SV) in human, chimpanzee and mouse. The same technology associated with 3-dimensional analysis was then performed on human and mouse pachytene nuclei from cytospin preparations and tissue cryosections. The human and the chimpanzee SVs were very similar, with a consistently small size and a high degree of condensation. The mouse SV was most often seen to be large and poorly condensed, although it did undergo progressive condensation during pachynema. These results suggest that the condensation of the sex chromosomes is not a prerequisite for the formation of the mouse SV, and that a different specific mechanism could be responsible for its formation. We also found that the X and Y chromosomes are organized into two separate and non-entangled chromatin domains in the SV of the three species. In each species, telomeres of the X and Y chromosomes remain clustered in a small area of the SV, even those without a pseudoautosomal region. The possible mechanisms involved in the organization of the sex chromosomes and in SV formation are discussed.
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14
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Morales A, Cavicchia JC. Seasonal changes of the blood-testis barrier in viscacha (Lagostomus maximus maximus): a freeze-fracture and lanthanum tracer study. Anat Rec (Hoboken) 1993; 236:459-64. [PMID: 8363051 DOI: 10.1002/ar.1092360306] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Adult male viscachas (Lagostomus maximus maximus) were gathered from their natural habitat during the period of complete spermatogenesis (June) and during the month of maximum testicular regression (August). The testes were processed by conventional electron microscopic technique using lanthanum nitrate (electron-dense intercellular tracer) to define the intercellular spaces below the inter-Sertoli tight junctions and by freeze-fracture techniques. During complete spermatogenesis the tracer surrounds spermatogonia, preleptotene, and leptotene spermatocytes and stops at the level of the inter-Sertoli tight junctions below all germ cells displaying synaptonemal complexes (zygotene-pachytene spermatocytes) and germ cells in more advanced stages of differentiation. Conversely, during testicular regression the tracer percolates all intercellular spaces between Sertoli cells and the remaining germ cells (spermatogonia and few preleptotene and leptotene spermatocytes). During complete spermatogenesis, freeze-fracture replicas exhibit numerous inter-Sertoli tight junction strands parallel to each other and to the basal lamina. During spermatogenesis decay, the inter-Sertoli tight junctions are found to be short, tortuous, frequently interrupted, and often associated with extented membranous areas of gap junctions.
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Affiliation(s)
- A Morales
- Instituto de Histologia y Embriologia, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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15
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Cavicchia JC, Sacerdote FL, Gutierrez LA. Nickel nitrate: a new junction permeability tracer for the study of the blood-testis barrier. Microsc Res Tech 1992; 20:34-42. [PMID: 1611149 DOI: 10.1002/jemt.1070200105] [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: 12/27/2022]
Abstract
With the purpose of evaluating a new intercellular tracer, nickel-K ferrocyanide, we compared results yielded by lanthanum with information provided by nickel. This was done in the seminiferous epithelium of Holtzman rats of several postnatal ages and in a wild local seasonal breeder Galea musteloides. Tissues were studied with transmission electron microscopy and freeze-fracture replications. Nickel tracing proved to delineate cell contours more intensely and less interruptedly than lanthanum. With regard to seasonal variations in adult galea, the limits of the barrier were similar to those described in other mammals: spermatogonia, preleptotene, and leptotene spermatocytes were surrounded by the tracer in the basal compartment. The zygotenepachytenes were contained in the lumenal compartment and tracers were stopped at the inter-Sertoli cell tight junctions. During the inactive spermatogenic phase in winter, the seminiferous epithelium contained Sertoli cells and occasional germ cells, never beyond the spermatocyte stage. The tracer filled intercellular spaces, indicating that the barrier was incompetent. Some resting germ cells showed nuclear hyperchromasia, karyolysis, organelle loss, cell shrinkage, and cell fusion leading to a multinucleated cells. The inter-Sertoli tight junctions were scanty and had randomly oriented and discontinuous junctional strands. Moreover, inter-Sertoli cell gap junctions proliferated. During the active spermatogenic phase in summer, junctions were numerous. Their junctional strands were parallel to each other, and continuous.
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Affiliation(s)
- J C Cavicchia
- Instituto de Histología y Embriología, CONICET, Mendoza, Argentina
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Cavicchia JC, Morales A. Characterization of nuclear pore distribution in freeze-fracture replicas of seminiferous tubules isolated by transillumination. Tissue Cell 1992; 24:75-84. [PMID: 1561625 DOI: 10.1016/0040-8166(92)90082-i] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Transilluminated seminiferous tubules were staged and utilized to determine the distribution of nuclear pore complexes in seminiferous tubules of the rat. Segments of seminiferous tubules of adult albino rats were separated and identified (in stages VII-VIII, IX-XI, XII-XIV, and V-VI), and then processed by freeze-fracture. Type A spermatogonia, the only spermatogonia located in seminiferous segments possessing stages IX-XI and XII-XIV, are oval cells in contact with the basal lamina. They either exhibit a random distribution of nuclear pores or a slight degree of clumping. Type B spermatogonia, found in segments possessing stages V-VI, exhibit, instead, a noticeable pore clustering. The identification of intermediate spermatogonia was not undertaken in this study. Preleptotene spermatocytes are easily identified in freeze-fracture by their location in segments with stages VII-VIII, by their arrangement in numerous groups between the basal lamina and the pachytene spermatocytes, and by their comparatively small size. They exhibit noticeable pore clustering. Leptotene (segments containing stages IX-XI) and zygotene (XII-XIV) spermatocytes show a more homogeneous distribution of nuclear pores. Pachytene spermatocytes are identified by their large size, by consistent detachment from the basal lamina and by being rather numerous and found in all the stages explored. Diplotene spermatocytes have the largest nuclei of all germ cells. They are always detached from the basal lamina and found only in seminiferous segments containing stage XIII. Pachytenes display a regular geometric array of pore aggregation with striking clustering, whereas diplotene nuclear pores takes on a random distribution. Secondary spermatocytes, only present in stage XIV intermingled with metaphase-anaphase profiles, are characterized in replicas by a paucity of evenly distributed nuclear pores.
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Affiliation(s)
- J C Cavicchia
- Instituto de Histologia y Embriologia, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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17
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Cavicchia JC, Sacerdote FL. Correlation between blood-testis barrier development and onset of the first spermatogenic wave in normal and in busulfan-treated rats: a lanthanum and freeze-fracture study. Anat Rec (Hoboken) 1991; 230:361-8. [PMID: 1867410 DOI: 10.1002/ar.1092300309] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Pregnant rats (day 13) received 10 mg/kg of Busulfan i.p. The seminiferous tubules of their offspring from post-natal age 1 day up to day 35 were examined with TEM after fixation plus intercellular tracers, and with freeze-fracture techniques. During this period, the inter-Sertoli tight junctions of controls increase both in number and in length. Between days 10 and 13 the seminiferous cords have numerous preleptotene and leptotene spermatocytes surrounded by tracer. The inter-Sertoli junctions are tortuous and predominantly perpendicular to the basal lamina. Between ages 13 and 20 days the seminiferous epithelium reaches zygotene-pachytene stages. The tracer is stopped at the inter-Sertoli junctions at this stage, whereas it still permeates tubules displaying preleptotene and leptotene spermatocytes. Freeze-fracture shows that the orientation of inter-Sertoli junctions has changed to parallel, both to each other and to the basal lamina. In the Busulfan-treated rats, the tubules continue having, up to post-natal day 30, only Sertoli cells and scanty spermatogonia. In these, lanthanum penetration goes as far as the apical Sertoli cell region; the inter-Sertoli junctions still show tortuous strands, and most are oriented perpendicular to the basal lamina. This indicates that formation of the first competent inter-Sertoli junctions is temporo-spatially simultaneous with the appearance of zygotene-pachytene spermatocytes.
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Affiliation(s)
- J C Cavicchia
- Instituto de Histología y Embriología IHEM, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo and CONICET, Mendoza, Argentina
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Tandler CJ, Solari AJ. An 'axis-like' material in the centromeric region of metaphase-I chromosomes from mouse spermatocytes. Genetica 1991; 84:39-49. [PMID: 1714848 DOI: 10.1007/bf00123983] [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: 12/28/2022]
Abstract
This study reports the persistence of axis-like structures in the centromeric region of both homologues during the metaphase-I and anaphase-I stages of meiotic division of mouse spermatocytes. A novel type of silver 'argentaffin' technique (NH4-Ag) is employed. This technique includes the treatment of glutaraldehyde-fixed tissues with dilute ammonium hydroxide followed by a reduction of aldehyde groups with sodium borohydride. Staining is accomplished with ammoniacal silver nitrate in darkness followed by sulfite washing. The lateral elements of synaptonemal complexes and the single chromosomal axes of diplotene spermatocytes show a prominent reactivity with this technique. The pattern of very small grains over condensed chromatin is uniform and gives only a light opacity to the electron beam. The presence of an axis-like structure is seen in every centromeric end of meiotic chromosomes at metaphase I and anaphase I. The chromatin (heterochromatin) that surrounds the centromeric filament and some material distributed in irregular linear arrays along some of the homologues also showed a higher electron opacity than the bulk of deoxyribonucleoprotein. While the former is related to C+ heterochromatin, the latter could represent dispersed material of diplotene axes. It is suggested that the disposal of axial material is differentially delayed at the centromeric regions. The present evidence supports the hypothesis that axial fragments or lateral-element segments persisting at these regions contribute to the cohesiveness of centromeres of sister chromatids during normal disjunction.
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Affiliation(s)
- C J Tandler
- Instituto de Biología Celular, Facultad de Medicina, Buenos Aires, Argentina
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19
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Biggiogera M, Kaufmann SH, Shaper JH, Gas N, Amalric F, Fakan S. Distribution of nucleolar proteins B23 and nucleolin during mouse spermatogenesis. Chromosoma 1991; 100:162-72. [PMID: 1710179 DOI: 10.1007/bf00337245] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The intracellular distribution of nucleolar phosphoproteins B23 and nucleolin was studied during mouse spermatogenesis, a process that is characterized by a progressive reduction of nucleolar activity. Biochemical analyses of isolated germ cell fractions were performed in parallel with the in situ ultrastructural immunolocalization of these two proteins by means of specific antibodies and colloidal gold markers, and by silver staining. RNA blot experiments showed that mRNA for nucleolin progressively decreased during spermatogenesis whereas mRNA for B23 increased in amount during early spermatogenic stages. Immunoblotting confirmed that both proteins were present during early spermatogenesis up to the round spermatid stage and absent from mature sperm. Immunoelectron microscopy revealed that in spermatogonia, leptotene and pachtyene spermatocytes, and in Golgi phase spermatids, B23 and nucleolin were localized in the dense fibrillar component and granular component of the nucleolus but not in the fibrillar centers. In the dense fibrillar residue of the cap phase spermatids, labeling with anti-nucleolin but not with anti-B23 was observed. During nucleolar inactivation, neither of the two polypeptides was dispersed to the nucleoplasm. Silver salts stained the fibrillar centers and dense fibrillar component but not the granular component of the nucleolus. Our results suggest that there is no direct relationship between nucleolar activity and the occurrence of B23 and nucleolin or silver staining. Moreover, we confirm that silver staining and the presence of B23 or nucleolin are not directly related to each other.
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Affiliation(s)
- M Biggiogera
- Centre of Electron Microscopy, University of Lausanne, Lausanne, Switzerland
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20
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Schultz MC. Three structures associated with the nucleolus in male rat germinal cells: round body, coiled body, and "nubecula" and general presence of round body at male meiosis. THE AMERICAN JOURNAL OF ANATOMY 1990; 189:11-23. [PMID: 1700593 DOI: 10.1002/aja.1001890103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In addition to chromosomes and nucleoli, three structures, i.e., round body, coiled body, and nubecula, are encountered in the nucleus during the meiotic prophase in male rats. These structures have been examined by electron microscopy in random and serial sections. The round body is a finely fibrillar, proteinaceous structure closely associated with the granular component of a nucleolus in rat spermatocytes and young spermatids. A similar structure has been observed in man, the monkey Macaca mulatta, the gastropod Achatina fulica, and the insect Locusta migratoria. Together with evidence from the literature, these results support the view that the round body is of general occurrence in the male meiocytes of eukaryotes and may, therefore, play a role in meiosis. The coiled body is a group of electron-dense elements called "coils", which average 35 nm in width, except after mid-pachytene when their size almost doubles. The coils are composed of 2-nm-wide filaments and 8 to 10-nm-wide granules, both of which are ribonucleoprotein. The coiled bodies are interpreted to be groups of "spliceosomes", that is, structures containing heterogeneous RNA and small nuclear RNA. A remarkable feature of the coiled body is its temporary disappearance at early pachytene and its reappearance at late pachytene, possibly due to drastic changes in the turnover rate of its component RNAs. The nubecula is a newly identified nuclear inclusion, composed of weakly staining threads loosely organized into a 560 nm-wide spheroid. It has been observed only in early pachytene nuclei.
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Affiliation(s)
- M C Schultz
- Department of Anatomy, McGill University, Montreal, Quebec, Canada
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Cavicchia JC, Sacerdote FL. Topography of the rat blood-testis barrier after intratubular administration of intercellular tracers. Tissue Cell 1988; 20:577-86. [PMID: 3238690 DOI: 10.1016/0040-8166(88)90059-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Intratubular injection of electron-opaque tracers (lanthanum hydroxide, peroxidase) by micromanipulation showed that the intercellular spaces of the adluminal compartment are in continuity with the lumen of the rat seminiferous tubule at all stages of the spermatogenic cycle. This continuity involves the intercellular spaces which surround zygotene spermatocytes and late leptotene spermatocytes in stages X-XI. The present observations would seem to cast doubt on the real existence of a third compartment, or intermediate compartment, in the seminiferous epithelium. In the material which, in addition to intratubular administration, had been treated with intravascular tracer perfusion, we found the presence of a parabasal region of interSertoli junctions where the tracer stopped whatever its direction. Freeze-fracture replicas exhibit interSertoli tight junctions arranged, from basal lamina to lumen, in three well-defined patterns: in the most basal area, which is the zone of free penetration of tracers from the peritubular environment, junctions are very sparse or absent; a belt of closely apposed continuous and parallel junctions, also parallel to the basal lamina, is the exclusion zone which prevents tracer penetration from either direction; the most apical membrane areas display irregularly arranged, loosely spaced and frequently interrupted rows of particles, most tending to be perpendicular to the basal lamina. This area corresponds to the territory where the intraluminally injected tracer permeates the interSertoli space.
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Affiliation(s)
- J C Cavicchia
- Instituto de Histologia y Embriologia, Facultad de Ciencias Médicas, U.N. Cuyo, Mendoza, Argentina
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Hubert J, Bourgeois CA. The nuclear skeleton and the spatial arrangement of chromosomes in the interphase nucleus of vertebrate somatic cells. Hum Genet 1986; 74:1-15. [PMID: 3530977 DOI: 10.1007/bf00278778] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The topologic distribution of interphase chromosomes established by using various cytologic methods and data concerning the DNA-nuclear skeleton interactions in isolated nuclear fractions were reviewed and discussed. Comparison of these different data clearly showed that the position of chromosomes observed in situ is in agreement with the results obtained from isolated nuclear fractions, indicating that all DNA molecules are bound to the peripheral nuclear skeleton. Moreover, the in situ position of the rDNA near the nuclear envelope can be correlated with the existence of a nucleolar skeleton connected to the peripheral nuclear skeleton. Taking into account the discrepant results regarding the actual existence of an internal nuclear skeleton, we attempted to analyze how the various nuclear skeletal structures described in the literature can be involved in both the distribution of chromosomes and in their chromatin organization. As many questions are still unanswered, we considered the modes of investigation that seem to be the most promising.
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23
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Glamann J. Crossing over in the male mouse as analysed by recombination nodules and bars. ACTA ACUST UNITED AC 1986. [DOI: 10.1007/bf02907321] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Miranda JC, Cavicchia JC. A permeability barrier in the testis of an insect Triatoma: A freeze-fracture and lanthanum tracer study. Tissue Cell 1986; 18:461-8. [DOI: 10.1016/0040-8166(86)90065-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/1986] [Indexed: 10/27/2022]
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25
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Asymmetry and resolution of the synaptonemal complex in the XY pair ofChinchilla laniger. Genetica 1985. [DOI: 10.1007/bf02424462] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Mirre C, Knibiehler B. Ultrastructural and functional variations in the spermatid nucleolus during spermiogenesis in the mouse. CELL DIFFERENTIATION 1985; 16:51-61. [PMID: 3986916 DOI: 10.1016/0045-6039(85)90607-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The localization, structure, and activity of the nucleolus-organizers (NORs) were studied during spermiogenesis in the mouse by light and electron microscopy procedures including NOR-silver-staining and actinomycin D treatment. After the two meiotic divisions the NORs resume their activity during the Golgi phase of spermatid differentiation (steps 1-3), and the nucleolus displays a specific 'padlock' structure containing the fibrillar components of an active nucleolus. This activity drops during the cap phase (steps 4-7) during which the nucleolus undergoes a segregation process of its components. No nucleolar structure is visible during the acrosomal and maturation phases of spermatid differentiation.
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27
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Schultz MC, Hermo L, Leblond CP. Structure, development, and cytochemical properties of the nucleolus-associated "round body" in rat spermatocytes and early spermatids. THE AMERICAN JOURNAL OF ANATOMY 1984; 171:41-57. [PMID: 6207723 DOI: 10.1002/aja.1001710105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The "round body," a spherical structure typically associated with a nucleolus in male germ cells of the rat, has been examined in the electron microscope using routine and cytochemical methods to determine its structure, composition, and mode of development. Cytochemical analysis indicates that the round body includes neither nucleic acid nor lipid, but is composed of nonhistone protein which appears in the form of 1.6-nm-wide fibrils. Development begins in late leptotene, when a single round body appears in each spermatocyte as an irregular spheroid located along the inner surface of the nuclear envelope. During subsequent stages of the meiotic prophase, the round body leaves the nuclear envelope, becomes a regular sphere, and gradually enlarges from a diameter of 0.4 micron in leptotene to 1.6 micron in diplotene. Concurrently, lacunae appear within its substance and enlarge. At each maturation division, the amount of round-body material is decreased by about half, presumably because the constituent proteins are dissociated at metaphase, distributed between the two daughter cells at telophase, and reconstituted into half-sized round bodies. As spermiogenesis proceeds, the round body shrinks gradually and disappears at step 8. Soon after its appearance at leptotene, the round body becomes associated with and is surrounded by the pars granulosa of one of the nucleoli. Moreover, 3H-uridine incorporation into nucleolar RNA is high as long as the size of the round body increases, but is low or absent when it decreases. It is possible, therefore, that the round body exerts some control on nucleolar activity in meiotic cells.
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28
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Cavicchia JC, Moviglia GA. The blood-testis barrier in the toad (Bufo arenarum Hensel): a freeze-fracture and lanthanum tracer study. Anat Rec (Hoboken) 1983; 205:387-96. [PMID: 6407358 DOI: 10.1002/ar.1092050404] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Intercellular junctions between Sertoli cells in the toad testis were studied by freeze-fracture and electron-opaque intercellular markers. These junctional specializations are characterized in thin sections by a series of focal fusions on the outer leaflets of both adjacent cell plasmalemmas, associated with bundles of fine filaments in the subjacent Sertoli cell cytoplasms. However, the wide subsurface cisterna of the endoplasmic reticulum, a component constantly associated with Sertoli cell junctions in mammals, is absent in the toad. The intravascularly injected lanthanum hydroxide, used as a tracer compound, gains access to the seminiferous tubules and surrounds spermatogonia and leptotene spermatocytes, but is persistently excluded from germ cells in later stages of development. This indicates that, as is the case in the mammalian testis, a permeability barrier to lanthanum is established which isolates all germ cells beyond leptotene spermatocytes. Freeze-fracture reveals the characteristic occluding junctions between Sertoli cells, but a variation in their geometric patterns was clearly observed in different regions of the toad seminiferous epithelium. The membrane-fractured faces of Sertoli cells embracing differentiating spermatids exhibit a deep junctional complex: up to 50 rows of particles between adjacent Sertoli cells separate these late germ cells from the periphery of the seminiferous tubules. Sertoli cells surrounding early germ cells generally exhibit, instead, a discontinuous, poorly developed network of interconnected rows of particles with few widely spaced strands. This seems to permit the percolation of the intercellular marker in areas of the seminiferous epithelium containing spermatogonia and leptotene spermatocytes.
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29
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DePhilip RM, Tres LL, Kierszenbaum AL. Stage-specific protein synthesis during rat spermatogenesis. Exp Cell Res 1982; 142:489-94. [PMID: 7173337 DOI: 10.1016/0014-4827(82)90396-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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30
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Wang HC, Juurlink BH. Demonstration of axial elements of sex vesicles of spermatocytes using Coomassie brilliant blue. STAIN TECHNOLOGY 1981; 56:19-23. [PMID: 6165100 DOI: 10.3109/10520298109067269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The axial element of sex chromosomes in the sex vesicle of rat and mouse spermatocytes has been visualized under the light microscope by the dye Coomassie brilliant blue (CBB). After staining in the CBB solution for 3-10 minutes, the axial elements appeared as darkly stained threads in the sex vesicles, whereas in controls stained with Giemsa or carbol fuchsin, the sex vesicles were usually uniformly stained. The axial elements are best seen when chromosome preparations were made by the flame drying technique. In rat spermatocytes the staining quality could be further improved by a brief treatment with trypsin solution (0.025%). The CBB staining procedure is simple and easily controllable. The results suggest that the CBB stained material is protein in nature and is more resistant to trypsin digestion than other nuclear proteins.
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31
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De Martino C, Capanna E, Nicotra MR, Natali PG. Immunochemical localization of contractile proteins in mammalian meiotic chromosomes. Cell Tissue Res 1980; 213:159-78. [PMID: 7006828 DOI: 10.1007/bf00236928] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Smooth muscle heavy myosin and actin have been detected in mouse and rat meiotic chromosomes, by indirect immunofluorescence performed on testis cryostat sections and isolated germ cells. Both contractile proteins are detectable in the nuclei of meiotic cells during the first prophase. The appearance and disappearance time of myosin and actin, however, is not synchronous. While actin is visible in small spots from resting to late diplotene spermatocytes, myosin appears as filaments in the primary spermatocytes from the zygotene to the early state of diplotene. The number of myosin filaments in the pachytene spermatocytes corresponds to the number of bivalent chromosomes, whereas actin spots constantly outnumber the pairing chromosomes by two units. These immunochemical observations suggest that the two contractile proteins are associated with the synaptonemal complex (SC). Myosin seems to be associated with the central region of the SC, while actin is present in its basal knob which is in connection with the nuclear membrane. The difference in number between myosin filaments and actin spots appears to be related to the peculiar behaviour of the pairing sex chromosomes. The presence of contractile proteins in the nuclei of primary spermatocytes seems to suggest that they might play a role in the process of pairing of homologous chromosomes.
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Abstract
Human spermatocytes processed with a modified microspreading technique which involves the use of sodium dodecyl-sulphate (SDS) have been used to construct synaptonemal complex (SC) karyotypes. Twenty two pachytene spermatocytes were selected for length quantitation. The mean values of relative lengths and centromeric indexes of each SC agree closely with values obtained by three-dimensional reconstructions (Holm and Rasmussen, 1977), except for SCs #4--5, 6--7 and 19--20. Absolute lengths are consistently longer in spreads (10.7% longer than in sections, on average). The mean total length of the SC complement is 258.7 micrometer. Six morphological types of XY pairs have been described. On the basis of the relationships between the XY pair, nucleolar development and autosome behavior, these six XY types are assumed to develop in succession. Type O XY pairs occur during late zygotene, types I and II XY pairs occur during early to mid-pachytene, and types III, IV and V occur during later pachytene substages. Alignment of the X and Y axes is observed at late zygotene, and formation of the SC occurs in relation with type I XY pairs. Progressive desynapsis occurs in types II and III. Splitting and fusion of the X and Y axes attain a maximum in types IV and V. The breakdown of the dense bodies associated with the X and Y axes occurs during stage V. --Bar-like structures, having a mean length of 2,100 A are associated with SCs in all the pachytene substages defined by the XY types. The average number of bars per nucleus is 46.2 (SD = 8.4, N = 20), and the average SC length per bar is 5.57 micrometer. The distribution along the SCs of 923 bars shows that near-termini locations are preferred (SC length per bar, 2.98 micrometer) and centromere regions are avoided (SC length per bar, 16.9 micrometer). --On the basis of these data, bars are similar to recombination nodules described in other organisms. The availability of a standard SC karyotype for microspreads and a temporal sequence given by the XY pair provide a basis for rapid screening of chromosome aberrations in human testicular biopsies.
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33
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Gravis CJ. Cytochemical localization of cations in the testis of the Syrian hamster, utilizing potassium-pyroantimonate. THE AMERICAN JOURNAL OF ANATOMY 1979; 154:245-65. [PMID: 760495 DOI: 10.1002/aja.1001540209] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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34
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Esponda P, Stockert JC. Localization of the synaptonemal complex under the light microscope. Chromosoma 1978; 68:83-90. [PMID: 80311 DOI: 10.1007/bf00330374] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The use of osmium tetroxide fixation followed by postreatment with p-phenylenediamine gives an opportunity of locating the synaptonemal complex (SC) under the light microscope in mouse testes and Allium cepa anthers. When semi-thin sections from these materials were observed under phase contrast optics or dark field microscopy, fine threads in the pachytene nuclei were clearly visible. Post-staining of semi-thin sections with ammoniacal silver increased the contrast of the SC and allowed for observations using a bright field illumination. Ultrathin sections of osmium tetroxide/p-phenylenediamine treated material showed that, under the electron microscope, this technique stains preferentially elements of the synaptonemal complex, while the surrounding chromatin remains unstained.
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35
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Abstract
Multiple complexes develop during metaphase I in normal human spermatocytes. Usually they form two separate bodies about 1 micron in diameter, composed of tripartite units and a denser matrix. The tripartite units are structurally identical to the components of the central space of synaptonemal complexes (SCs). Formation of the multiple complexes occurs by shedding of SC fragments from a few chromosomal regions at prometaphase I. The combined total length of central elements in each multiple complex is 1 to 3 micron. Multiple complexes remain as cytoplasmic, perinuclear bodies during telophase I and interphase of spermatocytes II, but they were not observed during or after the second meiotic division. Although multiple complexes are initially located in the spindle, they do not show microtubular attachments and seem to be passively moved towards the periphery.
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36
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Monesi V, Geremia R, D'Agostino A, Boitani C. Biochemistry of male germ cell differentiation in mammals: RNA synthesis in meiotic and postmeiotic cells. Curr Top Dev Biol 1978; 12:11-36. [PMID: 352625 DOI: 10.1016/s0070-2153(08)60592-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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37
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Holm PB, Rasmussen SW. Human meiosis I. The human pachytene karyotype analyzed by three dimensional reconstruction of the synaptonemal complex. ACTA ACUST UNITED AC 1977. [DOI: 10.1007/bf02910454] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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38
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39
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Mirre C, Stahl A. Ultrastructural study of nucleolar organizers in the quail oocyte during meiotic prophase I. JOURNAL OF ULTRASTRUCTURE RESEARCH 1976; 56:186-201. [PMID: 986477 DOI: 10.1016/s0022-5320(76)80165-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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40
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Elsevier SM, Ruddle FH. Location of genes coding for 18S and 28S ribosomal RNA within the genome of Mus musculus. Chromosoma 1975; 52:219-28. [PMID: 1183299 DOI: 10.1007/bf00332112] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cytological detection of cistrons coding for 18S and 28S ribosomal RNA (rRNA) within the genome of Mus musculus inbred strain SEC/1ReJ was accomplished using the technique of in situ hybridization. Metaphase chromosome spreads prepared from cultured fetal mouse cells were stained with quinacrine-HCl and photographed. After destaining, they were hybridized to Xenopus laevis tritiated 18S and 28S rRNA, specific activity 7.5 X 10(6) dpm/mug. Silver grains clustered over specific chromosomes were readily apparent after 4 months of autoradiographic exposure. The identity of the labelled chromosomes was established by comparing the autoradiographs to quinacrine photographs showing characteristic fluorescent banding of the chromosomes in each metaphase spread. The 18S and 28S rRNA was found to hybridize to chromosomes 12, 18, and 16. Statistical analysis of the grain distribution over 26 spreads revealed that the three chromosomes were significantly labelled. Grains over these chromosomes were concentrated in an area immediately distal to the centromere, a region which in chromosomes 12 and 18 in this particular strain is the site of a secondary constriction. The relative size of the secondary constrictions, long and thus prominent on chromosome 12, obvious but shorter on 18, and indistinguishable on chromosome 16, correlated with the average number of grains observed over the centromeric region of these chromosomes, 2.5, 1.0, and 0.78, respectively.
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41
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Solari AJ, Bianchi NO. The synaptic behaviour of the X and Y chromosomes in the marsupial Monodelphis dimidiata. Chromosoma 1975; 52:11-25. [PMID: 1175455 DOI: 10.1007/bf00285785] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The pairing behaviour of the X and Y chromosomes of Monodelphis dimidiata was studied with light and electron microscopy. Pairing of the sex chromosomes is delayed with respect to autosome synapsis. Both the X and the minute Y chromosome show an axis attached by its two ends to the nuclear envelope. Synapsis of the sex chromosomes occurs by the joining of the chromatin sheaths that surround the axes and by a small, three-layered structure close to the nuclear envelope. The X and Y chromosomes remain joined to each other during the diffuse stage and diplotene-diakinesis but they do not show a synaptonemal complex. During the diffuse stage a dense plate is formed at the boundary between the X-Y body and the nuclear envelope. During early metaphase a folded sheet is attached to the periphery of the X-Y body. This sheet is formed by a piece of the nuclear envelope carrying the dense plate and it shows transverse fibrils and a central element similar to synaptonemal-complex remains. No evidence of a non-chiasmate segregation mechanism was observed. Polarization of the axial ends of the sex chromosomes is observed after X-Y synapsis. These important departures from the X-Y pairing pattern of eutherian mammals are discussed and assumed to present a special mechanism for holding the minute Y joined to the X chromosome in this marsupial.
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42
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Ware RW. Three-dimensional reconstruction from serial sections. INTERNATIONAL REVIEW OF CYTOLOGY 1975; 40:325-440. [PMID: 1097356 DOI: 10.1016/s0074-7696(08)60956-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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43
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44
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45
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Galdieri M, Monesi V. Ribosomal RNA synthesis in spermatogonia and Sertoli cells of the mouse testis. Exp Cell Res 1973; 80:120-6. [PMID: 4783737 DOI: 10.1016/0014-4827(73)90282-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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46
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Tres LL, Kierszenbaum AL, Tandler CJ. Inorganic cations in the cell nucleus. Selective accumulation during meiotic prophase in mouse testis. J Cell Biol 1972; 53:483-93. [PMID: 4112542 PMCID: PMC2108725 DOI: 10.1083/jcb.53.2.483] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Earlier reports indicated the presence of significant amounts of inorganic salts in the nucleus. In the present study the possibility that this might be related to the transcription process was tested on seminiferous epithelium of the adult mouse, using potassium pyroantimonate as a fixative. The results indicated that a correlation exists between the inorganic cations comprising the pyroantimonate-precipitable fraction and the RNA synthetic activity. During meiotic prophase an accumulation of cation-antimonate precipitates occurs dispersed through the middle pachytene nuclei, the stage in which RNA synthesis reaches a maximum. At other stages (zygotene to diplotene), where RNA synthesis falls to a low level, that pattern is not seen; cation-antimonate deposits are restricted to a few masses in areas apparently free of chromatin. The condensed sex chromosomes, the heterochromatin of the "basal knobs," the axial elements, and the synaptonemal complexes are devoid of antimonate deposits during the meiotic prophase. The Sertoli cells, active in RNA synthesis in both nucleoplasm and nucleolus, show cation-antimonate deposits at these sites. In the nucleoplasm some "patches" of precipitates appear coincident with clusters of interchromatin granules; in the nucleolus the inorganic cations are mainly located in the fibrillar and/or amorphous areas, whereas relatively few are shown by the granular component. The condensed chromatin bodies associated with the nucleolus were always free of antimonate precipitates. It is suggested that the observed sites of inorganic cation accumulation within the nucleus may at least partially indicate the presence of RNA polymerases, the activity of which is dependent on divalent cations.
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47
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Comings DE, Okada TA. The chromatoid body in mouse spermatogenesis: evidence that it may be formed by the extrusion of nucleolar components. JOURNAL OF ULTRASTRUCTURE RESEARCH 1972; 39:15-23. [PMID: 4111665 DOI: 10.1016/s0022-5320(72)80003-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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48
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49
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Zenzes MT, Wolf U. [Pairing behaviour of the sex chromosomes during male meiosis of Microtus agrestis]. Chromosoma 1971; 33:41-7. [PMID: 5574764 DOI: 10.1007/bf00326382] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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50
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Solari AJ, Tres LL. The three-dimensional reconstruction of the XY chromosomal pair in human spermatocytes. J Cell Biol 1970; 45:43-53. [PMID: 5458999 PMCID: PMC2107993 DOI: 10.1083/jcb.45.1.43] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The spatial reconstruction of the XY pair of chromosomes from human spermatocytes has been made by the study of serial sections 1000 A in thickness. The sex pair during zygotene-pachytene forms a condensed mass of chromatin that has two filamentous, electron-opaque cores: the long and the short core. During early pachytene both cores have a common ending region, about 0.4-0.8 micro long. This common end is a synaptonemal complex, and each of the cores forms a lateral element of that complex. The cores become more convoluted during middle pachytene forming "ringlike bodies." Nucleoli from spermatocytes have three distinct regions: (a) granular; (b) dense fibrillar; and (c) clear intermediate. Occasional association of the XY pair and the heteropycnotic "basal knobs" results in apparent association of nucleoli and the sex pair in a minority of cells. The evidence presented is interpreted as a strong support of the hypothesis of homologous regions in the human XY pair.
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