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Abstract
Producing competent gametes is essential for transmitting genetic information throughout generations. Spermatogenesis is a unique example of rearrangements of genome packaging to ensure fertilization. After meiosis, spermatids undergo drastic morphological changes, perhaps the most dramatic ones occurring in their nuclei, including the transition into a protamine-packaged genome. In this issue of Genes & Development, Montellier and colleagues (pp. 1680-1692) shed new light on the molecular mechanisms regulating this transition by ascribing for the first time a function to a histone variant, TH2B, in the regulation of this process.
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Affiliation(s)
- Ana Boskovic
- U964, Institut National de la Santé et de la Recherche Médicale INSERM, Centre National de la Recherche Scientifique CNRS, Institut de Génétique et de Biologie Moléculaire et Cellulaire, F-67404 Illkirch, Cu de Strasbourg, France
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2
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Steilmann C, Paradowska A, Bartkuhn M, Vieweg M, Schuppe HC, Bergmann M, Kliesch S, Weidner W, Steger K. Presence of histone H3 acetylated at lysine 9 in male germ cells and its distribution pattern in the genome of human spermatozoa. Reprod Fertil Dev 2012; 23:997-1011. [PMID: 22127005 DOI: 10.1071/rd10197] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 05/04/2011] [Indexed: 12/28/2022] Open
Abstract
During spermatogenesis, approximately 85% of histones are replaced by protamines. The remaining histones have been proposed to carry essential marks for the establishment of epigenetic information in the offspring. The aim of the present study was to analyse the expression pattern of histone H3 acetylated at lysine 9 (H3K9ac) during normal and impaired spermatogenesis and the binding pattern of H3K9ac to selected genes within ejaculates. Testicular biopsies, as well as semen samples, were used for immunohistochemistry. Chromatin immunoprecipitation was performed with ejaculated sperm chromatin. HeLa cells and prostate tissue served as controls. Binding of selected genes was evaluated by semiquantitative and real-time polymerase chain reaction. Immunohistochemistry of H3K9ac demonstrated positive signals in spermatogonia, spermatocytes, elongating spermatids and ejaculated spermatozoa of fertile and infertile men. H3K9ac was associated with gene promoters (CRAT, G6PD, MCF2L), exons (SOX2, GAPDH, STK11IP, FLNA, PLXNA3, SH3GLB2, CTSD) and intergenic regions (TH) in fertile men and revealed shifts of the distribution pattern in ejaculated spermatozoa of infertile men. In conclusion, H3K9ac is present in male germ cells and may play a role during the development of human spermatozoa. In addition, H3K9ac is associated with specific regions of the sperm genome defining an epigenetic code that may influence gene expression directly after fertilisation.
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Affiliation(s)
- C Steilmann
- Department of Urology, Pediatric Urology and Andrology, Justus-Liebig University of Giessen, Rudolf Buchheim Str. 7, 35385 Giessen, Germany
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3
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Steilmann C, Cavalcanti MCO, Bergmann M, Kliesch S, Weidner W, Steger K. Aberrant mRNA expression of chromatin remodelling factors in round spermatid maturation arrest compared with normal human spermatogenesis. Mol Hum Reprod 2010; 16:726-33. [DOI: 10.1093/molehr/gaq054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Haraguchi CM, Mabuchi T, Hirata S, Shoda T, Tokumoto T, Hoshi K, Yokota S. Possible Function of Caudal Nuclear Pocket. J Histochem Cytochem 2007; 55:585-95. [PMID: 17312012 DOI: 10.1369/jhc.6a7136.2007] [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: 11/22/2022] Open
Abstract
Many temporarily functioning proteins are generated during the replacement of nucleoproteins in the nuclei of late spermatids and seem to be degraded in the nucleus. This study was designed to clarify the involvement of the ubiquitin-proteasome degradation system in the nucleus of rat developing spermatids. Thus, we studied the nuclear distribution of polyubiquitinated proteins (pUP) and proteasome in spermiogenic cells and sperm using postembedding immunoelectron microscopy. We divided the nuclear area of late spermatids into two regions: (1) a dense area composed of condensed chromatin and (2) a nuclear pocket in the neck region. The latter was located in the caudal nuclear region and was surrounded by redundant nuclear envelope. We demonstrated the presence of pUP in the dense area and nuclear pocket, proteasome in the nuclear pocket, and clear spots in the dense area of rat spermatids. Using quantitative analysis of immunogold labeling, we found that fluctuation of pUP and proteasome levels in late spermatogenesis was mostly synchronized with disappearance of histones and transitional proteins reported previously. In the nuclei of human sperm, pUP was detected in the dense area, whereas proteasome was in the nuclear vacuoles and clear spots. These results strongly suggest that pUP occur in the dense nuclear area of developing spermatids and that the ubiquitin-proteasome system is more actively operational in the nuclear pocket than dense area. Thus, the nuclear pocket might be the degradation site for temporarily functioning proteins generating during condensation of chromatin in late spermatids.
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Affiliation(s)
- Celina M Haraguchi
- Biology Laboratory, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo-shi, Yamanashi 409-3898, Japan
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Zarnescu O. Immunohistochemical distribution of hyperacetylated histone H4 in testis of paddlefish Polyodon spathula: ultrastructural correlation with chromatin condensation. Cell Tissue Res 2007; 328:401-10. [PMID: 17252243 DOI: 10.1007/s00441-006-0373-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 12/19/2006] [Indexed: 11/25/2022]
Abstract
The acetylation of core histones has been correlated with the deposition of free histones onto newly replicated DNA, transcriptional activity and the displacement of histones by protamines during spermiogenesis. The aim of the present study was to investigate the immunohistochemical distribution of hyperacetylated H4 during spermatogenesis in Polyodon spathula and to correlate these findings with the pattern of chromatin condensation in spermatids. In immature testis, the Sertoli cells showed more intense immunoreactivity for highly acetylated H4 than that of most primary spermatogonia. The testis of paddlefish at the beginning of spermatogenesis possessed early secondary spermatogonia and late secondary spermatogonia/preleptotene primary spermatocyte with intense nuclear immunoreactivity for highly acetylated H4. In seminiferous tubules in which secondary spermatogonia nuclei were intensely immunostained, Sertoli cell nuclei were unstained. Testes in late spermatogenesis contained tubules in which the immunohistochemical reaction for highly acetylated H4 was positive in the nuclei of preleptotene primary spermatocytes and secondary spermatocytes and in spermatids at the beginning of the elongation process. No immunostaining was found in round spermatids and spermatozoa. During the resting stage, immunostaining was confined to the nuclei of spermatogonia and the cells from the interstitial tissue. Transmission electron microscopy revealed that early spermatids had a round nucleus with filaments of fine chromatin that were dispersed or condensed in clumps. In later stages of maturation, the spermatids had slightly oval nuclei and homogeneous granular chromatin. The chromatin of advanced spermatids was organized into thick fibres. At the end of spermiogenesis, spermatozoan nuclei consisted of homogeneous highly compacted chromatin.
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Affiliation(s)
- Otilia Zarnescu
- Department of Animal Biology, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest-5, Romania.
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Manochantr S, Sretarugsa P, Chavadej J, Sobhon P. Chromatin organization and basic nuclear proteins in the male germ cells ofRana tigerina. Mol Reprod Dev 2004; 70:184-97. [PMID: 15570620 DOI: 10.1002/mrd.20191] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The process of chromatin condensation during spermiogenesis in Rana tigerina is similar to the heterochromatization in somatic cells, where 30 nm fibers are coalesced together into a dense mass in spermatozoa without changing their initial size and nucleosomal organization. This conclusion was supported by the finding that the full set of core histones (H2A, H2B, H3, H4) are still present in sperm chromatin, but histone H1 is replaced by its variant, H1V. Rabbit anti-sera were raised against histone H3, H1, H1V, and H5 (H1 variant in chick erythrocyte). Anti-histone H1 antiserum cross-reacted with histone H1V, which implied the presence of a common epitope. Anti-histone H1V and H5 also showed cross-reaction with each other but not with histone H1, which implied the presence of a common epitope not shared by histone H1. Immunocytochemical studies, using the above antibodies as probes, showed that histones H3 is present in all steps of spermatogenic and spermiogenic cells, and somatic cells including red blood cells, Sertoli cells, and Leydig cells, while histone H1 is present in all of the cells mentioned except in spermatozoa where it is replaced by histone H1V. Histone H1V appears in the early spermatids starting from spermatid 1 (St1), and it persists throughout the course of spermatid differentiation into spermatozoa. Histone H1V is also found in chromosomes of metaphase spermatocyte and red blood cells. Thus histone H1V may cause the final and complete condensation of chromatin in Rana spermatozoa, a process which is similar to the heterochromatization occurring in somatic cells such as metaphase chromosome and chick erythrocyte nucleus.
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Affiliation(s)
- Sirikul Manochantr
- Department of Anatomy, Faculty of Medicine, Thammasart University, Rangsit Campus, Patumthanee, Thailand
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Thompson EM, Legouy E, Renard JP. Mouse embryos do not wait for the MBT: chromatin and RNA polymerase remodeling in genome activation at the onset of development. DEVELOPMENTAL GENETICS 2000; 22:31-42. [PMID: 9499578 DOI: 10.1002/(sici)1520-6408(1998)22:1<31::aid-dvg4>3.0.co;2-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In Xenopus and Drosophila embryos, activation of the zygotic genome occurs after a series of rapid nuclear divisions in which DNA replication occupies most of the cell cycle. In these organisms, it has been proposed that zygotic transcription does not begin until a threshold nucleocytoplasmic ratio has been obtained in which repressive factors are titrated out and interphase becomes long enough to allow synthesis of transcripts. In mammalian embryos, however, a model of threshold nucleocytoplasmic ratios does not seem to apply, as beginning with the 1-cell stage, there are regulated cell cycles with the expression of zygotic transcripts during the cleavage period. By taking advantage of the slower kinetics at the onset of mouse development, we have characterized changes in chromatin structure and the basal transcription machinery throughout the transition from transcriptional incompetence, to minor activation of the zygotic genome during the 1-cell stage, and through major genome activation at the 2-cell stage. Further maturation of chromatin structure continues through subsequent cleavage cycles as a foundation for the first cellular differentiations in the blastocyst. The epigenetic chromatin modifications that occur during the cleavage period may have long range and inheritable effects and are undoubtedly important in the ability of the mammalian oocyte to remodel previously defined nuclear structures and cell fates.
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Affiliation(s)
- E M Thompson
- Unité de Biologie du Développement, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
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Kido T, Namiki H. Evidence that the PERF 15 Germ Cell Specific Protein Associates with DNA in the Presence of Ca2+. Zoolog Sci 1999. [DOI: 10.2108/zsj.16.497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Chen HY, Sun JM, Zhang Y, Davie JR, Meistrich ML. Ubiquitination of histone H3 in elongating spermatids of rat testes. J Biol Chem 1998; 273:13165-9. [PMID: 9582357 DOI: 10.1074/jbc.273.21.13165] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Because of the potential role of histone ubiquitination in altering chromatin structure, we characterized the levels of ubiquitination of specific histones in meiotic and postmeiotic germ cells in rat testes by two-dimensional gel electrophoresis. The levels of the major ubiquitinated histone forms, mono- and poly-ubiquitinated H2A, were highest in the pachytene spermatocyte stage, declined thereafter through the round spermatid stage, and reached their lowest levels in elongating spermatids. Three additional ubiquitinated histone species, besides H2A, were detected using anti-ubiquitin antibodies specifically in the fraction enriched in elongating spermatids. Based on their electrophoretic mobilities, they corresponded to uH3, uTH3, and uH2B. Polyubiquitinated forms of these proteins were also observed. The identity of these proteins was confirmed by immunoblotting with anti-H3 antisera and by differential extraction of the proteins from the nucleus with increasing salt concentrations. This is the first report of ubiquitination of H3 in vivo. We speculate that its ubiquitination could loosen the nucleosome structure in preparation for histone removal, be a consequence of nucleosome relaxation or disruption caused by other means, or target H3 for degradation.
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Affiliation(s)
- H Y Chen
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Manitoba, R3E 0W3 Canada
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10
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Abstract
In animal species, spermiogenesis, the late stage of spermatogenesis, is characterized by a dramatic remodelling of chromatin which involves morphological changes and various modifications in the nature of the nuclear basic proteins. According to the evolution of species, three situations can be observed: a) persistence of somatic histones or appearance of sperm-specific histones; b) direct replacement of histones by generally smaller and more basic proteins called protamines; and c) occurrence of a double nuclear basic protein transition: histones are not directly replaced by protamines but by intermediate basic proteins which are themselves replaced by one or several protamines. However, in some species, two kinds of intermediate basic proteins can be distinguished in spermatid nuclei: transition proteins and protamine precursors. Whereas transition proteins are not structurally related either to histones or to protamines, protamine precursors are further processed at the end of spermiogenesis to give rise to the mature protamine. The molecular characteristics of the protamines as well as number of protamine types present in the spermatozoon vary from species to species. In some cases, protamine-encoding genes, although present, are not expressed to a significant level. The diversity and the precise function of intermediate basic proteins remain open to discussion. Some of them are the precursors of protamines but the mechanism, sequential or not, as well as the enzyme(s) involved in the proteolytic processing, remain to be discovered.
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Affiliation(s)
- D Wouters-Tyrou
- Unité 459 INSERM, Laboratoire de Biologie Cellulaire, Faculté de Médecine, Lille, France
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Adenot PG, Mercier Y, Renard JP, Thompson EM. Differential H4 acetylation of paternal and maternal chromatin precedes DNA replication and differential transcriptional activity in pronuclei of 1-cell mouse embryos. Development 1997; 124:4615-25. [PMID: 9409678 DOI: 10.1242/dev.124.22.4615] [Citation(s) in RCA: 283] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the mouse embryo, transcriptional activation begins during S/G2 phase of the first cell cycle when paternal and maternal chromatin are still in separate nuclear entities within the same cytoplasm. At this time, the male pronucleus exhibits greater transcriptional activity than the female pronucleus. Since acetylation of histones in the nucleosome octamer exerts a regulatory influence on gene expression, we investigated changes in histone acetylation during the remodeling of paternal and maternal chromatin from sperm entry through to minor genome activation and mitosis. We found (1) neither mature sperm nor metaphase II maternal chromatin stained for hyperacetylated histone H4; (2) immediately following fertilization, hyperacetylated H4 was associated with paternal but not maternal chromatin while, in parthenogenetically activated oocytes, maternal chromatin became hyperacetylated; (3) in zygotes, differential levels and patterns of hyperacetylated H4 between male and female pronuclei persisted throughout most of G1 with histone deacetylases and acetyltransferases already active at this time; (4) when transcriptional differences are observed in S/G2, male and female pronuclei have equivalent levels of H4 hyperacetylation and DNA replication was not required to attain this equivalence and (5) in contrast to the lack of H4 hyperacetylation on gametic chromatin, chromosomes at the first mitosis showed distinct banding patterns of H4 hyperacetylation. These results suggest that sperm chromatin initially out-competes maternal chromatin for the pool of hyperacetylated H4 in the oocyte, that hyperacetylated H4 participates in the process of histone-protamine exchange in the zygote, and that differences in H4 acetylation in male and female pronuclei during G1 are translated across DNA replication to transcriptional differences in S/G2. Prior to fertilization, neither paternal nor maternal chromatin show memory of H4 hyperacetylation patterns but, by the end of the first cell cycle, before major zygotic genome activation at the 2-cell stage, chromosomes already show hyperacetylated H4 banding patterns.
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Affiliation(s)
- P G Adenot
- Unité de Biologie du Développement, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
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Alami-Ouahabi N, Veilleux S, Meistrich ML, Boissonneault G. The testis-specific high-mobility-group protein, a phosphorylation-dependent DNA-packaging factor of elongating and condensing spermatids. Mol Cell Biol 1996; 16:3720-9. [PMID: 8668189 PMCID: PMC231368 DOI: 10.1128/mcb.16.7.3720] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mammalian spermiogenesis is characterized by a striking restructuring of the spermatid chromatin caused by the replacement of nucleohistones with transition proteins and their subsequent replacement with nucleoprotamines. The onset of nuclear elongation and chromatin condensation in spermatids is accompanied by a general decrease in the transcriptional activity of the DNA. A recently identified testis-specific high-mobility-group (tsHMG) protein, similar to the human mitochondrial transcription factor I and to the linker-associated protein delta of Tetrahymena thermophila micronuclei, is thought to play a structural role in this process. We confirm by immunoblot analysis of fractionated germ cells that the presence of tsHMG is restricted to transcriptionally quiescent elongating and condensing spermatids. Purified recombinant tsHMG protein displays preferential binding to supercoiled plasmid DNA, which reversibly protects the DNA against the DNA-relaxing activity of eukaryotic topoisomerase I and also impairs the transcriptional activity of this template when assayed in vitro. The tsHMG protein can also introduce negative supercoils into a relaxed plasmid substrate in a topoisomerase I-dependent manner. We also show that the tsHMG protein is the substrate of a Ca2+-phospholipid-dependent protein kinase (protein kinase C) present in testis extracts of adult mice and demonstrate that phosphorylation by protein kinase C is required for both the DNA-binding and the topoisomerase I-dependent supercoiling activities of tsHMG. Our results support the hypothesis that the spermatid tsHMG protein is a topological factor (transition protein) that can modulate the activity of topoisomerase I. This activity could contribute to the important transition in chromatin structure which leads to the decrease in DNA metabolism observed at the early stages of spermatid elongation.
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Affiliation(s)
- N Alami-Ouahabi
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke, Quebec, Canada
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Unni E, Mayerhofer A, Zhang Y, Bhatnagar YM, Russell LD, Meistrich ML. Increased accessibility of the N-terminus of testis-specific histone TH2B to antibodies in elongating spermatids. Mol Reprod Dev 1995; 42:210-9. [PMID: 8562066 DOI: 10.1002/mrd.1080420210] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Changes in chromatin structure during spermatogenesis were investigated using a monoclonal antibody that immunoreacts with the N-terminus of the testis-specific histone TH2B. This monoclonal antibody, which had been raised against rat tyrosine hydroxylase (TH), cross-reacted with TH2B because of sequence homology at the N-termini of TH and TH2B. The epitope was localized to the N-terminus of TH2B as trypsin-digested chromatin which lacked the N-terminal tail did not react with anti-TH and preincubating anti-TH with a synthetic peptide made from the homologous sequence between TH2B and TH inhibited its binding to TH and TH2B. In histological sections of rat testis, the primary spermatocytes and round spermatids immunoreacted weakly, whereas elongating spermatids at steps 10-12 immunoreacted intensely with anti-TH. Increased staining of elongating spermatids was also observed in mouse and hamster by immunohistochemistry. However, immunoblotting proteins extracted from separated rat testis cells showed no increase in the TH2B content of these late steps of spermatids. The apparent increase in the immunohistochemical staining corresponds to increased accessibility of the epitope in the elongating spermatids. This indicated that the N-terminus of TH2B is less tightly bound to DNA or to other proteins at this time in preparation for the removal of TH2B and other histones.
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Affiliation(s)
- E Unni
- Department of Experimental Radiotherapy, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
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Meistrich ML, Trostle-Weige PK, Lin R, Bhatnagar YM, Allis CD. Highly acetylated H4 is associated with histone displacement in rat spermatids. Mol Reprod Dev 1992; 31:170-81. [PMID: 1372808 DOI: 10.1002/mrd.1080310303] [Citation(s) in RCA: 119] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The presence of highly acetylated histone H4 during spermatogenesis was studied to evaluate its correlation with the events of gene transcription, histone deposition, and histone displacement. We utilized an antibody raised to a pentaacetylated synthetic peptide that preferentially recognizes highly (tetra- and tri-) acetylated forms of rat testis H4. Electrophoretic separation of histones from enriched fractions of spermatogenic cells followed by detection of these forms by staining and by immunoblotting using this antibody showed that the highly acetylated forms were limited almost exclusively to spermatids beginning at step 11 of development. Immunoflurescence also revealed a striking polarity in the progression of histone from the spermatid nucleus. Highly acetylated H4 was displaced from the anterior to the caudal portion of the spermatid nucleus during steps 11 and 12, along with other histones, prior to their displacement by transition proteins. Thus, while monoacetylated and low levels of diacetylated forms of H4 were associated with stages at which histone deposition and transcription occur, the more highly acetylated forms appeared in high levels only at the stage at which histone displacement occurs.
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Affiliation(s)
- M L Meistrich
- Department of Experimental Radiotherapy, University of Texas M.D. Anderson Cancer Center, Houston
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McPherson SM, Longo FJ. Localization of DNase I-hypersensitive regions during rat spermatogenesis: stage-dependent patterns and unique sensitivity of elongating spermatids. Mol Reprod Dev 1992; 31:268-79. [PMID: 1315143 DOI: 10.1002/mrd.1080310408] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
DNase I-hypersensitivity of rat spermatogenic cells was analyzed 1) to establish overall patterns of hypersensitivity in individual cell types, 2) to correlate these patterns with known changes in chromatin organization and function, and 3) to provide a foundation for further analyses examining DNase I-hypersensitivity and the localization of specific genes during spermatogenesis. Parameters for in situ nick translation, using radioactive and fluorescent probes to visualize DNase I-hypersensitive regions (DHR), were established for fixed and sectioned testicular preparations, permeabilized cells, and isolated germ cell nuclei. As anticipated, the pattern of DHR changed in a cell-type specific manner during the course of spermatogenesis, reflective of known stage-dependent alterations in the composition and structure of both the chromatin and the nuclear lamina/matrix as well as changes in gene expression. DHR in preleptotene spermatocytes were primarily peripheral, while in pachytene spermatocytes they were localized along the condensed chromosomes. The pattern of DHR changed from "checkerboard" in steps 7-8 round spermatid nuclei to "lamellar" in steps 10-11 elongating spermatids. In steps 12-13 elongating spermatids. DHR were localized throughout the nuclei or in a graded manner--increasing from anterior to posterior and mirroring the pattern of chromatin condensation. However, unlike the case in other stages, DNA of steps 12-13 elongating spermatids was exquisitely sensitive to nick translation even in the absence of exogenous DNase I. In contrast to the labeling of earlier stages, steps 16-19 spermatids and mature spermatozoa did not demonstrate DNase I-hypersensitivity under any conditions employed. A variety of agents that interact with topoisomerase II and DNA (teniposide, novobiocin, ethidium bromide, and adenosine triphosphate) were tested to determine the basis for the unique sensitivity to nick translation of steps 12-13 elongating spermatids. None of the agents tested, however, affected this unique labeling. The sensitivity of steps 12-13 elongating spermatids to nick translation in the absence of exogenous nuclease indicators the presence of endogenous nicks, which may relieve torsional stress and aid rearrangement as the chromatin is packaged into a form characteristic of the mature spermatozoon.
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Affiliation(s)
- S M McPherson
- Department of Anatomy, University of Iowa, Iowa City 52242
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16
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Oliva R, Dixon GH. Vertebrate protamine genes and the histone-to-protamine replacement reaction. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1991; 40:25-94. [PMID: 2031084 DOI: 10.1016/s0079-6603(08)60839-9] [Citation(s) in RCA: 297] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- R Oliva
- Unidad de Fisiologia, Grupo de Genética Molecular, Barcelona, Spain
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17
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Akama K, Maruyama R, Mochizuki H, Tobita T. Boar transition protein 2 and 4 isolated from late spermatid nuclei by high-performance liquid chromatography. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1041:264-8. [PMID: 2268673 DOI: 10.1016/0167-4838(90)90282-k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The boar late spermatid nuclei retaining transition proteins (TPs) could be obtained from the testis by the use of antipain to inhibit TP-degrading proteinases of the nuclei. The enzymes detected in acid extract including the basic proteins were inactivated by reduction and carboxymethylation of the proteins. The reduced and carboxymethylated basic proteins were fractionated by differential precipitation between 3% trichloroacetic acid (TCA) and 3-20% TCA. From the 3% TCA-precipitate, boar TP2 and TP4 were isolated by high-performance liquid chromatography (HPLC) on Nucleosil 300 7C18. The two TPs were characterized by acid urea- and SDS-polyacrylamide gel electrophoreses and amino acid analysis. Boar TP2 closely resembled rat and mouse TP2s, and ram protein 3 in its high content of serine and basic amino acids, the presence of cysteine and molecular weight. Boar TP4 was similar to ram protein P1 in its high content of basic amino acids, the presence of cysteine and molecular weight. But the TP2 and TP4 differed in electrophoretic mobility on acid urea-gel and solubility in 3% TCA from those of the other species. The HPLC used here also enabled us to efficiently separate boar TP1, TP2, TP3 and TP4, and to estimate that the amount of the TP2, TP3 and TP4 was about 1/8, 1/4 and 1/4 that of the TP1, respectively.
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Affiliation(s)
- K Akama
- Department of Chemistry, Faculty of Science, Chiba University, Japan
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18
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Markose ER, Rao MR. Testis-specific histone H1t is truly a testis-specific variant and not a meiotic-specific variant. Exp Cell Res 1989; 182:279-83. [PMID: 2653854 DOI: 10.1016/0014-4827(89)90298-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Immunoblotting studies using highly specific polyclonal anti-histone H1t-IgG, which was extensively characterized by us previously, did not produce a signal with any of the histone H1 subtypes of either 1-day-old or adult rat ovarian nuclei. The absence of histone H1t in ovarian nuclei was also confirmed by indirect immunofluorescence studies. It is concluded, therefore, that histone H1t is truly a testis-specific histone variant and not a meiotic-specific variant.
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Affiliation(s)
- E R Markose
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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19
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Kleene KC, Flynn JF. Characterization of a cDNA clone encoding a basic protein, TP2, involved in chromatin condensation during spermiogenesis in the mouse. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)45373-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Abstract
The nick-translation procedure without external addition of DNase was performed in situ on sections of various rat organs to detect possible DNA single-strand breaks (nicks) in normal tissues. The freshly frozen sections were briefly fixed in ethanol/acetone and nick-translated in the presence of E. coli DNA polymerase I. A significant difference in the amount of nuclear reaction was found among the different cell populations as detected by autoradiography following incorporation of tritiated TTP as well as by histochemical staining following incorporation of biotin-dUTP into nuclei. Such incorporation of triphosphates was localized in the DNA and was entirely dependent on E. coli DNA polymerase I. The nuclei with the highest reactivity were found in skeletal muscle cells, lymphocytes in various lymphatic organs, the proliferative cells in the gastrointestinal tract, stratified squamous epithelial cells, duct epithelial cells of salivary gland and the maturing spermatids in the seminiferous tubules. These results suggest that, under the conditions adopted, the cells in various tissues reveal different chromatin structures resulting in varying rates of nick translation reaction. Such difference(s) in chromatin structure, presumably including that in the number of DNA single-strand breaks or in the level of endogenous nuclease activity, may be associated with the mechanisms involved in cell growth and differentiation.
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Grimes SR. Nuclear proteins in spermatogenesis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1986; 83:495-500. [PMID: 3514107 DOI: 10.1016/0305-0491(86)90285-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mammalian somatic type histone variants are replaced or supplemented in early primary spermatocytes and possibly spermatogonia by testis specific and testis enriched histone variants. The testis complement of histones is replaced entirely by transition basic proteins in mid-spermatids. This transition is accompanied by a dramatic reduction of thermal stability of mid-spermatid chromatin which may be due in part to hyperacetylation of histone H4. The transition basic proteins are replaced by protamines which are arginine-rich and contain cysteine.
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22
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Poccia D. Remodeling of nucleoproteins during gametogenesis, fertilization, and early development. INTERNATIONAL REVIEW OF CYTOLOGY 1986; 105:1-65. [PMID: 3539853 DOI: 10.1016/s0074-7696(08)61061-x] [Citation(s) in RCA: 199] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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