Diversity of chromatin condensation patterns, nuclear reorganization, evolution and phylogenetic distribution of sperm nuclear basic proteins in fish

Like other eukaryotes, Saccharomyces cerevisiae spatially organizes its chromosomes within the nucleus. In G1 phase, the yeast’s 32 telomeres are clustered into 6–10 foci that dynamically interact with the nuclear membrane. Here we show that, when cells leave the division cycle and enter quiescence, telomeres gather into two to three hyperclusters at the nuclear membrane vicinity. This localization depends on Esc1 but not on the Ku proteins. Telomere hypercluster formation requires the Sir complex but is independent of the nuclear microtubule bundle that specifically assembles in quiescent cells. Importantly, mutants deleted for the linker histone H1 Hho1 or defective in condensin activity or affected for histone H4 Lys-16 deacetylation are impaired, at least in part, for telomere hypercluster formation in quiescence, suggesting that this process involves chromosome condensation. Finally, we establish that telomere hypercluster formation is not necessary for quiescence establishment, maintenance, and exit, raising the question of the physiological raison d’être of this nuclear reorganization.

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DEFECTIVE HISTONE TRANSITION DURING SPERMIOGENESIS IN HETEROZYGOUS SEGREGATION DISTORTER MALES OF DROSOPHILA MELANOGASTER

Genetics ◽

10.1093/genetics/101.1.57 ◽

1982 ◽

Vol 101 (1) ◽

pp. 57-69

Author(s):

Elizabeth Hauschteck-Jungen ◽

Daniel L Hartl

Keyword(s):

Drosophila Melanogaster ◽

Chromatin Condensation ◽

Fluorescent Dye ◽

Basic Proteins ◽

Normal Transition ◽

Segregation Distorter

ABSTRACT Males of Drosophila melanogaster that are heterozygous for the segregation distorter (SD) chromosome produce a gross excess of SD-bearing offspring because most of the non-SD-bearing sperm are dysfunctional. These dysfunctional sperm exhibit abnormalities in chromatin condensation and compaction during spermiogenesis. Use of the fluorescent dye sulfoflavine, which is specific for basic proteins, has now revealed that the dysfunctional sperm are also defective in the normal transition from somatic to spermatid-specific histones.

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Detection and mapping of interactions between chromatin and the nuclear envelope in drosophila embryos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140191 ◽

1995 ◽

Vol 53 ◽

pp. 764-765

Author(s):

W.F. Marshall ◽

A.F. Dernburg ◽

B. Harmon ◽

J.W. Sedat

Keyword(s):

Nuclear Envelope ◽

Chromatin Condensation ◽

Three Dimensional ◽

Physiological Role ◽

Nuclear Surface ◽

Intact Cells ◽

Molecular Determinants ◽

Surface Harmonic ◽

Drosophila Embryos

Interactions between chromatin and nuclear envelope (NE) have been implicated in chromatin condensation, gene regulation, nuclear reassembly, and organization of chromosomes within the nucleus. To further investigate the physiological role played by such interactions, it will be necessary to determine which loci specifically interact with the nuclear envelope. This will not only facilitate identification of the molecular determinants of this interaction, but will also allow manipulation of the pattern of chromatin-NE interactions to probe possible functions. We have developed a microscopic approach to detect and map chromatin-NE interactions inside intact cells.Fluorescence in situ hybridization (FISH) is used to localize specific chromosomal regions within the nucleus of Drosophila embryos and anti-lamin immunofluorescence is used to detect the nuclear envelope. Widefield deconvolution microscopy is then used to obtain a three-dimensional image of the sample (Fig. 1). The nuclear surface is represented by a surface-harmonic expansion (Fig 2). A statistical test for association of the FISH spot with the surface is then performed.

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Effects of Mg2+ on Chromatic Structure in Isolated Chicken Liver Nuclei

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158194 ◽

1990 ◽

Vol 48 (3) ◽

pp. 130-131

Author(s):

Soichiro Arai ◽

Yuh H. Nakanishi

Keyword(s):

Chromatin Structure ◽

Room Temperature ◽

Osmium Tetroxide ◽

Divalent Cations ◽

Chromatin Condensation ◽

Chicken Liver ◽

Electron Microscopic ◽

Razor Blade ◽

Microscopic Studies ◽

Liver Nuclei

Although many electron microscopic studies on extracted chromatin have provided considerable information on chromatin condensation induced by divalent cations, there is only a little literature available on the effects of divalent cations on chromatin structure in intact nuclei. In the present study, the effects of Mg2+ on chromatin structure in isolated chicken liver nuclei were examined over a wide concentration range of Mg2+ by scanning electron microscopy.Nuclei were prepared from chicken liver by the method of Chauveau et al. with some modifications. The nuclei were suspended in 25 mM triethanolamine chloride buffer (pH7.4) with 1 mM EDTA or in the buffer with concentrations of MgCl2 varying from 1 to 50 mM. After incubation for 1 min at 0°C, glutaraldehyde was added to 1.8% and the nuclei were fixed for 1 h at 4°C. The fixed nuclei were mixed with 15% gelatin solution warmed at about 40°C, and kept at room temperature until the mixture set. The gelatin containing the nuclei was fixed with 2% glutaraldehyde for 2-4 h, and cut into small blocks. The gelatin blocks were conductive-stained with 2% tannic acid and 2% osmium tetroxide, dehydrated in a graded series of ethanol, and freeze-cracked with a razor blade in liquid nitrogen.

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Absence of temporal ordering of apoptotic features in heat-shock treated leukemia and lymphoma cell lines

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166257 ◽

1996 ◽

Vol 54 ◽

pp. 758-759

Author(s):

D. W. Fairbain ◽

M.D. Standing ◽

K.L. O'Neill

Keyword(s):

Heat Shock ◽

Cell Lines ◽

Chromatin Condensation ◽

Membrane Integrity ◽

Resistant Cell ◽

Membrane Blebbing ◽

Late Loss ◽

Induced Apoptosis ◽

Dying Cells ◽

In Cells

Apoptosis is a genetically defined response to physiological stimuli that results in cellular suicide. Features common to apoptotic cells include chromatin condensation, oligonucleosomal DNA fragmentation, membrane blebbing, nuclear destruction, and late loss of ability to exclude vital dyes. These characteristics contrast markedly from pathological necrosis, in which membrane integrity loss is demonstrated early, and other features of apoptosis, which allow a non-inflammatory removal of dead and dying cells, are absent. Using heat shock-induced apoptosis as a model for examining stress response in cells, we undertook to categorize a variety of human leukemias and lymphomas with regard to their response to heat shock. We were also interested in determining whether a common temporal order was followed in cells dying by apoptosis. In addition, based on our previous results, we investigated whether increasing heat load resulted in increased apoptosis, with particular interest in relatively resistant cell lines, or whether the mode of death changed from apoptosis to necrosis.

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Laser scanning confocal microscopic analysis of cytoskeletal and nuclear reorganization in live Drosophila embryos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146710 ◽

1993 ◽

Vol 51 ◽

pp. 174-175

Author(s):

William Theurkauf

Keyword(s):

Laser Scanning ◽

Microscopic Analysis ◽

Large Cell ◽

Early Embryo ◽

Drosophila Embryo ◽

Cortical Actin ◽

Nuclear Reorganization ◽

Cytoskeletal Elements ◽

Microtubule Structure ◽

Drosophila Embryos

Cell division in eucaryotes depends on coordinated changes in nuclear and cytoskeletal components. In Drosophila melanogaster embryos, the first 13 nuclear divisions occur without cytokinesis. During the final four divisions, nuclei divide in a uniform monolayer at the surface of the embryo. These surface divisions are accompanied by dramatic changes in cortical actin and microtubule structure (Karr and Alberts, 1986), and inhibitor studies indicate that these changes are essential to orderly mitosis (Zalokar and Erk, 1976). Because the early embryo is syncytial, fluorescent probes introduced by microinjection are incorporated in structures associated with all of the nuclei in the blastoderm. In addition, the nuclei divide synchronously every 10 to 20 min. These characteristics make the syncytial blastoderm embryo an excellent system for the analysis of mitotic reorganization of both nuclear and cytoskeletal elements. However, the Drosophila embryo is a large cell, and resolution of cytoskeletal filaments and nuclear structure is hampered by out-of focus signal.

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Magnesium Chloride is an Effective Therapeutic Agent for Prostate Cancer

Functional Foods in Health and Disease ◽

10.31989/ffhd.v8i1.368 ◽

2018 ◽

Vol 8 (1) ◽

pp. 62 ◽

Cited By ~ 2

Author(s):

Julianna Maria Santos ◽

Fazle Hussain

Keyword(s):

Prostate Cancer ◽

Magnesium Chloride ◽

Epithelial Mesenchymal Transition ◽

Chromatin Condensation ◽

Myosin Ii ◽

In Vivo Studies ◽

Migration Speed ◽

Mesenchymal Transition

Background: Reduced levels of magnesium can cause several diseases and increase cancer risk. Motivated by magnesium chloride’s (MgCl2) non-toxicity, physiological importance, and beneficial clinical applications, we studied its action mechanism and possible mechanical, molecular, and physiological effects in prostate cancer with different metastatic potentials.Methods: We examined the effects of MgCl2, after 24 and 48 hours, on apoptosis, cell migration, expression of epithelial mesenchymal transition (EMT) markers, and V-H+-ATPase, myosin II (NMII) and the transcription factor NF Kappa B (NFkB) expressions.Results: MgCl2 induces apoptosis, and significantly decreases migration speed in cancer cells with different metastatic potentials. MgCl2 reduces the expression of V-H+-ATPase and myosin II that facilitates invasion and metastasis, suppresses the expression of vimentin and increases expression of E-cadherin, suggesting a role of MgCl2 in reversing the EMT. MgCl2 also significantly increases the chromatin condensation and decreases NFkB expression.Conclusions: These results suggest a promising preventive and therapeutic role of MgCl2 for prostate cancer. Further studies should explore extending MgCl2 therapy to in vivo studies and other cancer types.Keywords: Magnesium chloride, prostate cancer, migration speed, V-H+-ATPase, and EMT.

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