scholarly journals Meiotic Telomere Distribution and Sertoli Cell Nuclear Architecture Are Altered in Atm- andAtm-p53-Deficient Mice

2000 ◽  
Vol 20 (20) ◽  
pp. 7773-7783 ◽  
Author(s):  
Harry Scherthan ◽  
Martin Jerratsch ◽  
Sonu Dhar ◽  
Y. Alan Wang ◽  
Stephen P. Goff ◽  
...  
Keyword(s):  
Ataxia Telangiectasia ◽  
Meiotic Prophase ◽  
Nuclear Periphery ◽  
Nuclear Architecture ◽  
Gonadal Atrophy ◽  
Atm Protein ◽  
Genotoxic Insult ◽  
Atm Signaling ◽  
Deficient Mice

ABSTRACT The ataxia telangiectasia mutant (ATM) protein is an intrinsic part of the cell cycle machinery that surveys genomic integrity and responses to genotoxic insult. Individuals with ataxia telangiectasia as well as Atm −/− mice are predisposed to cancer and are infertile due to spermatogenesis disruption during first meiotic prophase. Atm −/−spermatocytes frequently display aberrant synapsis and clustered telomeres (bouquet topology). Here, we used telomere fluorescent in situ hybridization and immunofluorescence (IF) staining of SCP3 and testes-specific histone H1 (H1t) to spermatocytes of Atm- and Atm-p53-deficient mice and investigated whether gonadal atrophy in Atm-null mice is associated with stalling of telomere motility in meiotic prophase. SCP3-H1t IF revealed that mostAtm−/− p53 −/− spermatocytes degenerated during late zygotene, while a few progressed to pachytene and diplotene and some even beyond metaphase II, as indicated by the presence of a few round spermatids. InAtm−/− p53 −/− meiosis, the frequency of spermatocytes I with bouquet topology was elevated 72-fold. Bouquet spermatocytes with clustered telomeres were generally void of H1t signals, while mid-late pachytene and diploteneAtm−/− p53 −/− spermatocytes displayed expression of H1t and showed telomeres dispersed over the nuclear periphery. Thus, it appears that meiotic telomere movements occur independently of ATM signaling. Atm inactivation more likely leads to accumulation of spermatocytes I with bouquet topology by slowing progression through initial stages of first meiotic prophase and an ensuing arrest and demise of spermatocytes I. Sertoli cells (SECs), which contribute to faithful spermatogenesis, in theAtm mutants were found to frequently display numerous heterochromatin and telomere clusters—a nuclear topology which resembles that of immature SECs. However,Atm −/− SECs exhibited a mature vimentin and cytokeratin 8 intermediate filament expression signature. Upon IF with ATM antibodies, we observed ATM signals throughout the nuclei of human and mouse SECs, spermatocytes I, and haploid round spermatids. ATM but not H1t was absent from elongating spermatid nuclei. Thus, ATM appears to be removed from spermatid nuclei prior to the occurrence of DNA nicks which emanate as a consequence of nucleoprotamine formation.

scholarly journals Atm Inactivation Results in Aberrant Telomere Clustering during Meiotic Prophase

1999 ◽  
Vol 19 (7) ◽  
pp. 5096-5105 ◽  
Author(s):  
Tej K. Pandita ◽  
Christoph H. Westphal ◽  
Melanie Anger ◽  
Satin G. Sawant ◽  
Charles R. Geard ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Nuclear Matrix ◽  
Meiotic Prophase ◽  
Nuclear Periphery ◽  
Early Prophase ◽  
Telomeric Dna ◽  
Gonadal Atrophy ◽  
Significant Difference ◽  
Atm Protein ◽  
And Control

ABSTRACT A-T (ataxia telangiectasia) individuals frequently display gonadal atrophy, and Atm −/− mice show spermatogenic failure due to arrest at prophase of meiosis I. Chromosomal movements take place during meiotic prophase, with telomeres congregating on the nuclear envelope to transiently form a cluster during the leptotene/zygotene transition (bouquet arrangement). Since the ATM protein has been implicated in telomere metabolism of somatic cells, we have set out to investigate the effects of Atm inactivation on meiotic telomere behavior. Fluorescent in situ hybridization and synaptonemal complex (SC) immunostaining of structurally preserved spermatocytes I revealed that telomere clustering occurs aberrantly inAtm −/− mice. Numerous spermatocytes ofAtm −/− mice displayed locally accumulated telomeres with stretches of SC near the clustered chromosome ends. This contrasted with spermatogenesis of normal mice, where only a few leptotene/zygotene spermatocytes I with clustered telomeres were detected. Pachytene nuclei, which were much more abundant in normal mice, displayed telomeres scattered over the nuclear periphery. It appears that the timing and occurrence of chromosome polarization is altered in Atm −/− mice. When we examined telomere-nuclear matrix interactions in spermatocytes I, a significant difference was observed in the ratio of soluble versus matrix-associated telomeric DNA sequences between meiocytes ofAtm −/− and control mice. We propose that the severe disruption of spermatogenesis during early prophase I in the absence of functional Atm may be partly due to altered interactions of telomeres with the nuclear matrix and distorted meiotic telomere clustering.

scholarly journals Lateral Elements Inside Synaptonemal Complex-Like Polycomplexes in ndt80 Mutants of Yeast Bind DNA

Genetics ◽  
2003 ◽  
Vol 163 (2) ◽  
pp. 539-544 ◽  
Author(s):  
Hasanuzzaman Bhuiyan ◽  
Gunilla Dahlfors ◽  
Karin Schmekel
Keyword(s):  
In Situ Hybridization ◽  
Electron Microscope ◽  
Synaptonemal Complex ◽  
Immunoelectron Microscopy ◽  
Meiotic Prophase ◽  
Lateral Element ◽  
Homologous Chromosomes ◽  
Meiotic Prophase I ◽  
Dna Antibodies

Abstract The synaptonemal complex (SC) keeps the synapsed homologous chromosomes together during pachytene in meiotic prophase I. Structures that resemble stacks of SCs, polycomplexes, are sometimes found before or after pachytene. We have investigated ndt80 mutants of yeast, which arrest in pachytene. SCs appear normal in spread chromosome preparations, but are only occasionally found in intact nuclei examined in the electron microscope. Instead, large polycomplexes occur in almost every ndt80 mutant nucleus. Immunoelectron microscopy using DNA antibodies show strong preferential labeling to the lateral element parts of the polycomplexes. In situ hybridization using chromosome-specific probes confirms that the chromosomes in ndt80 mutants are paired and attached to the SCs. Our results suggest that polycomplexes can be involved in binding of chromosomes and possibly also in synapsis.

scholarly journals Nuclear Position and Shape Deformation of Chromosome 8 Territories in Pancreatic Ductal Adenocarcinoma

2011 ◽  
Vol 34 (1-2) ◽  
pp. 21-33 ◽  
Author(s):  
Sylvia Timme ◽  
Eberhard Schmitt ◽  
Stefan Stein ◽  
Jutta Schwarz-Finsterle ◽  
Jenny Wagner ◽  
...  
Keyword(s):  
Nuclear Periphery ◽  
Nuclear Architecture ◽  
Neoplastic Cell ◽  
Carcinoma Cells ◽  
Chromosome 8 ◽  
Ductal Adenocarcinoma ◽  
Cell Nuclei ◽  
Formalin Fixed Paraffin ◽  
Transcriptional Alterations ◽  
Functional Relevance

Cell type specific radial positioning of chromosome territories (CTs) and their sub-domains in the interphase seem to have functional relevance in non-neoplastic human nuclei, while much less is known about nuclear architecture in carcinoma cells and its development during tumor progression. We analyzed the 3D-architecture of the chromosome 8 territory (CT8) in carcinoma and corresponding non-neoplastic ductal pancreatic epithelium. Fluorescence-in-situ-hybridization (FISH) with whole chromosome painting (WCP) probes on sections from formalin-fixed, paraffin wax-embedded tissues from six patients with ductal adenocarcinoma of the pancreas was used. Radial positions and shape parameters of CT8 were analyzed by 3D-microscopy. None of the parameters showed significant inter-individual changes. CT8 was localized in the nuclear periphery in carcinoma cells and normal ductal epithelial cells. Normalized volume and surface of CT8 did not differ significantly. In contrast, the normalized roundness was significantly lower in carcinoma cells, implying an elongation of neoplastic cell nuclei. Unexpectedly, radial positioning of CT8, a dominant parameter of nuclear architecture, did not change significantly when comparing neoplastic with non-neoplastic cells. A significant deformation of CT8, however, accompanies nuclear atypia of carcinoma cells. This decreased roundness of CTs may reflect the genomic and transcriptional alterations in carcinoma.

scholarly journals Expression and localization of the mRNA for DNA (cytosine-5)- methyltransferase in mouse seminiferous tubules.

1994 ◽  
Vol 42 (9) ◽  
pp. 1271-1276 ◽  
Author(s):  
M Numata ◽  
T Ono ◽  
S Iseki
Keyword(s):  
In Situ Hybridization ◽  
Significant Role ◽  
Meiotic Prophase ◽  
Oligonucleotide Probe ◽  
Mouse Testis ◽  
Seminiferous Tubules ◽  
Hybridization Histochemistry ◽  
In Situ Hybridization Histochemistry

DNA (cytosine-5)-methyltransferase (DNA MTase) is the only enzyme known to be involved in the methylation of mammalian DNA. Although the expression of DNA MTase gene is abundant in the testis, little is known about the role of this enzyme during spermatogenesis. We examined the distribution of DNA MTase mRNA in mouse testis by in situ hybridization histochemistry with an oligonucleotide probe. The mRNA signal was observed in the seminiferous tubules and was localized predominantly in spermatogonia and spermatocytes, particularly during the earlier steps of meiotic prophase I, with maximal intensity in the early pachytene cells. These results suggest some significant role for DNA MTase in spermatogenesis.

scholarly journals Stable Brain ATM Message and Residual Kinase-Active ATM Protein in Ataxia-Telangiectasia

2011 ◽  
Vol 31 (20) ◽  
pp. 7568-7577 ◽  
Author(s):  
J. Li ◽  
J. Chen ◽  
H. V. Vinters ◽  
R. A. Gatti ◽  
K. Herrup
Keyword(s):  
Ataxia Telangiectasia ◽  
Atm Protein

Chromosome condensation induced by geminivirus infection of mature plant cells

2000 ◽  
Vol 113 (7) ◽  
pp. 1149-1160 ◽  
Author(s):  
H.W. Bass ◽  
S. Nagar ◽  
L. Hanley-Bowdoin ◽  
D. Robertson
Keyword(s):  
Coat Protein ◽  
Chromatin Condensation ◽  
Nuclear Periphery ◽  
Nuclear Architecture ◽  
Plant Cells ◽  
Image Data ◽  
Chromosome Condensation ◽  
Fish Analysis ◽  
Viral Dna ◽  
Plant Dna

Tomato golden mosaic virus (TGMV) is a geminivirus that replicates its single-stranded DNA genome through double-stranded DNA intermediates in nuclei of differentiated plant cells using host replication machinery. We analyzed the distribution of viral and plant DNA in nuclei of infected leaves using fluorescence in situ hybridization (FISH). TGMV-infected nuclei showed up to a sixfold increase in total volume and displayed a variety of viral DNA accumulation patterns. The most striking viral DNA patterns were bright, discrete intranuclear compartments, but diffuse nuclear localization was also observed. Quantitative and spatial measurements of high resolution 3-dimensional image data revealed that these compartments accounted for 1–18% of the total nuclear volume or 2–45% of the total nuclear FISH signals. In contrast, plant DNA was concentrated around the nuclear periphery. In a significant number of nuclei, the peripheral chromatin was organized as condensed prophase-like fibers. A combination of FISH analysis and indirect immunofluorescence with viral coat protein antibodies revealed that TGMV virions are associated with the viral DNA compartments. However, the coat protein antibodies failed to cross react with some large viral DNA inclusions, suggesting that encapsidation may occur after significant viral DNA accumulation. Infection by a TGMV mutant with a defective coat protein open reading frame resulted in fewer and smaller viral DNA-containing compartments. Nevertheless, nuclei infected with the mutant virus increased in size and in some cases showed chromosome condensation. Together, these results established that geminivirus infection alters nuclear architecture and can induce plant chromatin condensation characteristic of cells arrested in early mitosis.

The testis-specific transcript (ferT) of the tyrosine kinase FER is expressed during spermatogenesis in a stage-specific manner

1990 ◽  
Vol 10 (9) ◽  
pp. 5021-5025
Author(s):  
E Keshet ◽  
A Itin ◽  
K Fischman ◽  
U Nir
Keyword(s):  
In Situ Hybridization ◽  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Meiotic Prophase ◽  
Hybridization Analysis ◽  
Pachytene Stage ◽  
Specific Transcript ◽  
Specific Manner

ferT is a testis-specific transcript of FER encoding a truncated version of the potential tyrosine kinase. Using in situ hybridization analysis, we found that ferT was transiently expressed during spermatogenesis and that expression was restricted to spermatocytes at the pachytene stage of meiotic prophase. This pattern of expression is unprecedented by other tyrosine kinases and suggests a role for ferT in a particular stage of spermatogenesis.

Increased muscle fatigability in GLUT-4-deficient mice

2002 ◽  
Vol 282 (2) ◽  
pp. E348-E354 ◽  
Author(s):  
M. Gorselink ◽  
M. R. Drost ◽  
K. F. J. de Brouwer ◽  
G. Schaart ◽  
G. P. J. van Kranenburg ◽  
...  
Keyword(s):  
Peak Power ◽  
Fiber Type ◽  
Flexor Muscle ◽  
Glut 4 ◽  
Muscle Complex ◽  
Alternative Routes ◽  
Deficient Mice ◽  
Shortening Contractions ◽  
Contractile Performance

GLUT-4 plays a predominant role in glucose uptake during muscle contraction. In the present study, we have investigated in mice whether disruption of the GLUT-4 gene affects isometric and shortening contractile performance of the dorsal flexor muscle complex in situ. Moreover, we have explored the hypothesis that lack of GLUT-4 enhances muscle fatigability. Isometric performance normalized to muscle mass during a single tetanic contraction did not differ between wild-type (WT) and GLUT-4-deficient [GLUT-4(−/−)] mice. Shortening contractions, however, revealed a significant 1.4-fold decrease in peak power per unit mass, most likely caused by the fiber-type transition from fast-glycolytic fibers (IIB) to fast-oxidative fibers (IIA) in GLUT-4(−/−) dorsal flexors. In addition, the resting glycogen content was significantly lower (34%) in the dorsal flexor complex of GLUT-4(−/−) mice than in WT mice. Moreover, the muscle complex of GLUT-4(−/−) mice showed enhanced susceptibility to fatigue, which may be related to the decline in the muscle carbohydrate store. The significant decrease in relative work output during the steady-state phase of the fatigue protocol suggests that energy supply via alternative routes is not capable to compensate fully for the lack of GLUT-4.

scholarly journals Upregulation of Cardiac IL-10 and Downregulation of IFN-γin Balb/c IL-4−/−in Acute Chagasic Myocarditis due to Colombian Strain ofTrypanosoma cruzi

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Marcos Vinicius da Silva ◽  
Vera Lúcia de Almeida ◽  
Wendyson Duarte de Oliveira ◽  
Natália Carasek Matos Cascudo ◽  
Pollyana Guimarães de Oliveira ◽  
...  
Keyword(s):  
Acute Phase ◽  
Experimental Infection ◽  
Cardiac Tissue ◽  
Histopathological Analysis ◽  
Nest Density ◽  
Cytokine Levels ◽  
Splenic Cells ◽  
Immune System Regulation ◽  
Deficient Mice

Inflammatory response in Chagas disease is related to parasite and host factors. However, immune system regulation has not been fully elucidated. Thus, this study is aimed at evaluating IL-4 influence on acute phase ofTrypanosoma cruziexperimental infection through dosage of cytokine levels in cardiac homogenate of infected Balb/c WT and Balb/c IL-4−/−as well as its histopathological repercussions. For such purpose, mice were divided into two groups: an infected group with 100 forms of the Colombian strain and an uninfected group. After 21 days of infection, animals were euthanized and the blood, spleen, and heart were collected. The spleen was used to culture splenic cells in 48 h. Subsequently, cytokines TNF-α, IL-12p70, IL-10, IFN-γ, and IL-17 were measured in the blood, culture supernatant, and heart apex by ELISA. The base of the heart was used for histopathological analysis. From these analysis, infected Balb/c IL-4−/−mice showed milder inflammatory infiltrate compared to Balb/c WT, but without changes in nest density and collagen deposition. IL-4 absence culminated in lower cardiac tissue IFN-γproduction, although it did not affect TNF-αexpression in situ. It also decreased TNF-αsystemic production and increased IL-10, both systemically andin situ. In addition, IL-4 absence did not influence IL-17 expression. Splenocytes of IL-4-deficient mice produced higher amounts of IFN-γ, TNF-α, and IL-17 and lower amounts of IL-10. Thus, IL-4 absence in acute phase of experimental infection withT. cruziColombian strain reduces myocarditis due to lower IFN-γproduction and greater IL-10 productionin situand this pattern is not influenced by splenocyte general repertoire.

scholarly journals Metformin Reverses the Enhanced Myocardial SR/ER–Mitochondria Interaction and Impaired Complex I-Driven Respiration in Dystrophin-Deficient Mice

2021 ◽  
Vol 8 ◽  
Author(s):  
Claire Angebault ◽  
Mathieu Panel ◽  
Mathilde Lacôte ◽  
Jennifer Rieusset ◽  
Alain Lacampagne ◽  
...  
Keyword(s):  
Complex I ◽  
Early Stage ◽  
Intrinsic Activity ◽  
Proximity Ligation Assay ◽  
Proximity Ligation ◽  
Skeletal Muscle Dysfunction ◽  
Species Production ◽  
Therapeutic Perspective ◽  
Deficient Mice

Besides skeletal muscle dysfunction, Duchenne muscular dystrophy (DMD) exhibits a progressive cardiomyopathy characterized by an impaired calcium (Ca2+) homeostasis and a mitochondrial dysfunction. Here we aimed to determine whether sarco-endoplasmic reticulum (SR/ER)–mitochondria interactions and mitochondrial function were impaired in dystrophic heart at the early stage of the pathology. For this purpose, ventricular cardiomyocytes and mitochondria were isolated from 3-month-old dystrophin-deficient mice (mdx mice). The number of contacts points between the SR/ER Ca2+ release channels (IP3R1) and the porine of the outer membrane of the mitochondria, VDAC1, measured using in situ proximity ligation assay, was greater in mdx cardiomyocytes. Expression levels of IP3R1 as well as the mitochondrial Ca2+ uniporter (MCU) and its regulated subunit, MICU1, were also increased in mdx heart. MICU2 expression was however unchanged. Furthermore, the mitochondrial Ca2+ uptake kinetics and the mitochondrial Ca2+ content were significantly increased. Meanwhile, the Ca2+-dependent pyruvate dehydrogenase phosphorylation was reduced, and its activity significantly increased. In Ca2+-free conditions, pyruvate-driven complex I respiration was decreased whereas in the presence of Ca2+, complex I-mediated respiration was boosted. Further, impaired complex I-mediated respiration was independent of its intrinsic activity or expression, which remains unchanged but is accompanied by an increase in mitochondrial reactive oxygen species production. Finally, mdx mice were treated with the complex I modulator metformin for 1 month. Metformin normalized the SR/ER-mitochondria interaction, decreased MICU1 expression and mitochondrial Ca2+ content, and enhanced complex I-driven respiration. In summary, before any sign of dilated cardiomyopathy, the DMD heart displays an aberrant SR/ER-mitochondria coupling with an increase mitochondrial Ca2+ homeostasis and a complex I dysfunction. Such remodeling could be reversed by metformin providing a novel therapeutic perspective in DMD.

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