Search Results
Results 401 - 450 of 1159
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Manskikh V N - - 2006
We studied the relationship between mitotic regimen and incidence of micronuclei in liver and bone marrow cells of tailless amphibians under the effect of genotoxic carcinogen N-nitroso-N-methylcarbamide. Micronuclei appeared in amphibian somatic cells normally and after mutagenic exposure as a result of abnormal mitosis and of "interphase chromatin diminution". This ...
Boyne Michael T MT - - 2006
Top Down analysis revealed that at least fourteen genes encoding histone H2A are coexpressed in HeLa cells. Characterization of these species revealed that all except H2A.Z and H2A.F/Z were alpha-N-acetylated, H2A.O and H2A.C,D,I,N,P were the most abundant, and those exceeding approximately 10% abundance lacked post-translational modifications. This unequivocal identification of ...
Liu, Gin-Yun
The mitosis to interphase transition in higher eukaryotic cells is characterized by reassembly of the nuclear envelope, decondensation of the chromosomes, and reformation of the nucleolus. Coincident with reassembly of the nuclear envelope, nucleocytoplasmic trafficking is also restored, which allows for reestablishment of the nuclear and cytoplamsic compartments. To determine ...
Blazquez Cristina - - 2006
KDR (kinase insert domain receptor) phosphorylation induces several effects which lead eventually to cell proliferation and survival. The precise mechanisms by which KDR, once it is activated, communicates with the nucleus are starting to be understood but have not yet been completely unravelled. Two in vitro studies on animal cell ...
Gurdon J B - - 2006
This is a personal historical account of events leading from the earliest success in vertebrate nuclear transfer to the current hope that nuclear reprogramming may facilitate cell replacement therapy. Early morphological evidence in Amphibia for the toti- or multipotentiality of some nuclei from differentiated cells first established the principle of ...
Håkelien Anne-Mari - - 2006
Directly turning a somatic cell type into another would be beneficial for producing replacement cells for therapeutic purposes. To this end, novel cell reprogramming strategies are being developed. We describe here methods for functionally reprogramming a somatic cell using an extract derived from another somatic cell type. The procedure involves ...
Collas Philippe - - 2006
Recent evidence indicates that nuclear and cytoplasmic extracts from undifferentiated cells can reprogram gene expression and promote pluripotency in otherwise more developmentally restricted cell types. Notably, extracts of embryonal carcinoma cells or embryonic stem cells have been shown to elicit a shift in the transcriptional program of target cells to ...
Hewitson Tim D - - 2006
Monoclonal antibodies to proliferation associated antigens have long been used to histologically localize mitogenesis. However, techniques that distinguish cells in the synthetic or S phase have tended to rely on the in vivo incorporation of tritiated thymidine or thymidine analogs such as bromodeoxyuridine. The necessity to pulse with these labels ...
Håkelien Anne-Mari - - 2006
The direct transformation of one somatic cell type into another somatic cell type would be beneficial for producing isogenic replacement cells for therapeutic use. Various approaches for altering cell fate are being developed, including methods for differentiating stem cells isolated from somatic tissues. This chapter describes a procedure for turning ...
Komatsu Naoki - - 2006
Current chemotherapy of advanced non-small cell lung cancer (NSCLC) produces only a modest increase in survival time. New approaches are needed for this disease. The development of lung cancer is associated with silencing tumor suppressor genes that can occur not only by deletion or mutation, but also by epigenetic changes ...
Smetana K - - 2006
The diameter of nucleoli was measured in human bone marrow early granulocytic precursors after visualization by a simple cytochemical method for demonstration of RNA. Such method facilitated to clearly see nucleolar bodies without perinucleolar chromatin, including those of micronucleoli. The bone marrow of patients suffering from chronic myeloid leukaemia (untreated ...
Moreno-Moreno Olga - - 2006
Centromere identity is determined by the formation of a specialized chromatin structure containing the centromere-specific histone H3 variant CENP-A. The precise molecular mechanism(s) accounting for the specific deposition of CENP-A at centromeres are still poorly understood. Centromeric deposition of CENP-A, which is independent of DNA replication, might involve specific chromatin ...
Grigoryev Sergei A - - 2006
All cells that constitute mature tissues in an eukaryotic organism undergo a multistep process of cell differentiation. At the terminal stage of this process, cells either cease to proliferate forever or rest for a very long period of time. During terminal differentiation, most of the genes that are required for ...
Strahl Thomas - - 2005
Phosphatidylinositol 4-kinase, Pik1, is essential for viability. GFP-Pik1 localized to cytoplasmic puncta and the nucleus. The puncta colocalized with Sec7-DsRed, a marker of trans-Golgi cisternae. Kap95 (importin-beta) was necessary for nuclear entry, but not Kap60 (importin-alpha), and exportin Msn5 was required for nuclear exit. Frq1 (frequenin orthologue) also is essential ...
Laskey Ron - - 2005
Compared to sperm nuclei, nuclei from adult somatic cells replicate inefficiently in frog egg extract. In this issue of Cell, Lemaitre et al. (2005) show that pre-exposure of erythrocyte nuclei to a mitotic extract removes this difference, reorganizes the chromatin into shorter loops, and allows replication at much shorter intervals ...
Kipp Benjamin R - - 2005
OBJECTIVE: To determine which nuclear morphologic and background features are most associated with normal and abnormal chromosome patterns in urine cells evaluated by fluorescence in situ hybridization (FISH) with Vysis UroVysion (Downers Grove, Illinois, USA). STUDY DESIGN: One hundred specimens were analyzed and the nuclear morphologic and background features compared ...
Marks Paul A - - 2005
Histone deacetylase (HDAC) inhibitors are a new class of targeted anticancer agents. Several HDAC inhibitors are in clinical trials and have shown significant activity against a spectrum of both haematological and solid tumours at doses that are well tolerated by patients. HDACs and histone acetyltransferases can, by reversible acetylation, modify ...
McNairn Adrian J - - 2005
The origin recognition complex (ORC) is a conserved heterohexamer required for the formation of pre-replication (pre-RC) complexes at origins of DNA replication. Many studies of ORC subunits have been carried out in transformed human cell lines but the properties of ORC in primary cells have not been addressed. Here, we ...
Adelfalk Caroline - - 2005
Mutations in the lamin A gene have been shown, among other defects, to give rise to Hutchinson-Gilford progeria syndrome (HGPS) and to atypical Werner syndrome (WS), both of which are progeroid disorders. Here, we have investigated well-characterized WS patient cell strains that are compound heterozygous for mutations in the WRN ...
Hake Sandra B - - 2006
Covalent histone modifications and the incorporation of histone variants bring about changes in chromatin structure that in turn alter gene expression. Interest in non-allelic histone variants has been renewed, in part because of recent work on H3 (and other) histone variants. However, only in mammals do three non-centromeric H3 variants ...
Chen Jie - - 2005
Quercetin (QU) and trichostatin A (TSA) are promising anticancer drugs. While QU mainly exerts its anticancer activity through scavenging reactive oxygen species (ROS), the anticancer activity of TSA was attributed to its inhibition on histone deacetylases (HDAC). In the present study it was investigated, whether the combination of QU and ...
Kostova Nora N - - 2005
Histone H1(0) is a linker histone subvariant present in tissues of low proliferation rate. It is supposed to participate in the expression and maintenance of the terminal differentiation phenotype. The aim of this work was to study histone H1(0) distribution in human breast carcinoma and its relationship with the processes ...
Rockel Thomas Dino - - 2005
The ubiquitin proteasome system plays a fundamental role in the regulation of cellular processes by degradation of endogenous proteins. Proteasomes are localized in both, the cytoplasm and the cell nucleus, however, little is known about nuclear proteolysis. Here, fluorogenic precursor substrates enabled detection of proteasomal activity in nucleoplasmic cell fractions ...
Wakayama Sayaka - - 2005
The current success rate of cloned mice from adult somatic cell nuclei is very low, whereas it is relatively high for cloned mice from ES cell nuclei. In this experiment, we examined whether the success rate of cloning from somatic cells could be improved via nuclear transfer embryonic stem cells ...
Ruan Chun - - 2005
Recombination enhancer (RE) is essential for regulating donor preference during yeast mating type switching. In this study, by using minichromosome affinity purification (MAP) and mass spectrometry, we found that yeast Ku80p is associated with RE in MATa cells. Chromatin immunoprecipitation assays confirmed its occupancy in vivo. Deletion of YKU80 results ...
Fang Yuda - - 2005
The organization and dynamics of the genome have been shown to influence gene expression in many organisms. Data from mammalian tissue culture cells have provided conflicting conclusions with regard to the extent to which chromatin organization is inherited from mother to daughter nuclei. To gain insight into chromatin organization and ...
Levi Valeria - - 2005
Increasing evidence points to a dynamical compartmentalization of the cell nucleus, yet the mechanisms by which interphase chromatin moves and is positioned within nuclei remain unclear. Here, we study the dynamics of chromatin in vivo applying a novel particle-tracking method in a two-photon microscope that provides approximately 10-fold higher spatial ...
Villar Garea, Ana
Genetic alterations and deregulation of the epigenetic mechanisms collaborate in the initiation and progression of cancer. In contrast to the genetic defects, the epigenetic abnormalities are potentially reversible. This fact has driven the search for drugs that induce selectively changes in the epigenetic patterns of the tumor cells and thus ...
Gao Shan - - 2005
The physiological and pathophysiological functions of PAI-1 are related to its expression by specific cell types in normal and diseased tissues. We analysed the contribution of DNA methylation to the variation in PAI-1 mRNA levels in five cell lines. We found varying frequencies of methylation of 25 CpGs in the ...
Lammerding Jan - - 2005
Emery-Dreifuss muscular dystrophy can be caused by mutations in the nuclear envelope proteins lamin A/C and emerin. We recently demonstrated that A-type lamin-deficient cells have impaired nuclear mechanics and altered mechanotransduction, suggesting two potential disease mechanisms (Lammerding, J., P.C. Schulze, T. Takahashi, S. Kozlov, T. Sullivan, R.D. Kamm, C.L. Stewart, ...
McNairn Adrian J - - 2005
In yeast, the Origin Recognition Complex (ORC) is bound to replication origins throughout the cell-cycle, but in animal cells, there are conflicting data as to whether and when ORC is removed from chromatin. We find ORC1, 2 and ORC4 to be metabolically stable proteins that co-fractionate with chromatin throughout the ...
Spada Fabio - - 2005
Histone post-translational modifications mark distinct structural and functional chromatin states but little is known of their involvement in the progression of different cell cycle types across phylogeny. We compared temporal and spatial dynamics of histone H4 post-translational modifications during both mitotic and endoreduplicative cycles of the urochordate, Oikopleura dioica, and ...
Taipale Mikko - - 2005
Reversible histone acetylation plays an important role in regulation of chromatin structure and function. Here, we report that the human orthologue of Drosophila melanogaster MOF, hMOF, is a histone H4 lysine K16-specific acetyltransferase. hMOF is also required for this modification in mammalian cells. Knockdown of hMOF in HeLa and HepG2 ...
Wittich Sybille - - 2005
Histone deacetylase (HDAC) inhibitors are a novel class of promising anti-cancer agents. Little information is available on the capacity of structurally different HDAC inhibitors to induce terminal cell differentiation in different cell types in relation to enzyme inhibition and subtype selectivity. Consequently, the aim of this study was to provide ...
Trus M R - - 2005
Acute myeloblastic leukemia (AML) may be classified in a number of ways. Using the French American British classification, the M3 form of the disease or acute promyelocytic leukemia (APL) has been found to be sensitive in vitro and in vivo to the retinoid all trans retinoic acid (ATRA). The mechanism ...
Schütz Wolfgang - - 2005
The mammalian lamin B2 gene codes for two proteins, the somatic lamin B2 and the germ line-specific lamin B3. Lamin B3 lacks the N-terminus and a part of the alpha-helical rod domain present in lamin B2. These domains are substituted by 84 amino acids unique for lamin B3. When ectopically ...
Rocchi Paola - - 2005
Histone acetyltransferase and histone deacetylase (HDAC) determine the acetylation status of histones, and thereby control the regulation of gene expression. HDAC inhibitors have been found to inhibit the growth of a variety of tumor cells in vitro and in vivo. We demonstrated previously that the short-chain fatty acid compound butyrate ...
Sibani Sahar - - 2005
The Ku heterodimer, an abundant nuclear protein, binds DNA replication origins in a sequence-specific manner and promotes initiation. In this study, using HCT116 Ku80+/- haplo-insufficient and Orc2(delta/-) hypomorphic cells, the order of binding of Ku and the human origin recognition complex (HsORC) was determined. The nuclear expression of Ku80 was ...
Schütz Wolfgang - - 2005
Lamins are members of a multigene family of structural nuclear envelope (NE) proteins. Differentiated mammalian somatic cells express lamins A, C, B1, and B2. The composition and organization of the nuclear lamina of mammalian spermatogenic cells differ significantly from that of somatic cells as they express lamin B1 as well ...
Corsi L - - 2005
PBR is involved in numerous biological functions, including steroid biosynthesis, mitochondrial oxidative phosphorylation and cell proliferation. The presence of PBR at the perinuclear/nuclear subcellular level has been demonstrated in aggressive breast cancer cell lines and human glioma cells where it seems to be involved in cell proliferation. In our study ...
Alberio Ramiro - - 2005
The mechanisms governing nuclear reprogramming have not been fully elucidated yet; however, recent studies show a universally conserved ability of both oocyte and egg components to reprogram gene expression in somatic cells. The activation of genes associated with pluripotency by oocyte/egg components may require the remodeling of nuclear structures, such ...
Vani G - - 2005
The effects of exogenous histone H1 on estrogen receptor status of human breast cancer MCF 7 cells were investigated in presence and absence of estrogen. Exogenous histone H1 was significantly cytotoxic in a dose- and time-dependent manner. Cell cycle analysis revealed a significant increase in the percentage of cell accumulation ...
Kim In Ah - - 2005
Histone deacetylase inhibitors (HDIs) are emerging as potentially useful components in anticancer therapy. In this study, we tried to confirm the radiosensitizing effect of trichostatin A (TSA) on a panel of human carcinoma cell lines and elucidate its mechanism of interaction. A549, HeLa and Caski cells were exposed to TSA ...
Takahashi Kohta - - 2005
CENP-A is a centromere-specific histone H3 variant that is- essential for faithful chromosome segregation in all eukaryotes thus far investigated. We genetically identified two factors, Ams2 and Mis6, each of which is required for the correct centromere localization of SpCENP-A (Cnp1), the fission yeast homologue of CENP-A. Ams2 is a ...
Wu Rong - - 2005
Mono-, di-, and trimethylation of specific histone residues adds an additional level of complexity to the range of histone modifications that may contribute to a histone code. However, it has not been clear whether different methylated states reside stably at different chromatin sites or whether they represent dynamic intermediates at ...
McDevit Daniel C - - 2005
The Igkappa locus is recombined following initiation of a signaling cascade during the early pre-B stage of B cell development. The Ig kappa3' enhancer plays an important role in normal B cell development by regulating kappa locus activation. Quantitative analyses of kappa3' enhancer chromatin structure by restriction endonuclease accessibility and ...
Garrett Francine E - - 2005
The murine Igh locus has a 3' regulatory region (3' RR) containing four enhancers (hs3A, hs1,2, hs3B, and hs4) at DNase I-hypersensitive sites. The 3' RR exerts long-range effects on class switch recombination (CSR) to several isotypes through its control of germ line transcription. By measuring levels of acetylated histones ...
Manochantr Sirikul - - 2005
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 ...
Li Yan - - 2005
Post-translational modifications of core histone proteins play a key role in chromatin structure and function. Here, we study histone post-translational modifications during reentry of protoplasts derived from tobacco mesophyll cells into the cell cycle and evaluate their significance for progression through mitosis. Methylation of histone H3 at lysine residues 4 ...
Gurdon J B - - 2005
When nuclei of somatic cells are transplanted to enucleated eggs of Xenopus, a complete reprogramming of nuclear function can take place. To identify mechanisms of nuclear reprogramming, somatic nuclei can be transplanted to growing meiotic oocytes of Xenopus, and stem cell genes activated without DNA replication. The combination of somatic ...
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