Search results for "Cell Nucleus"
showing 10 items of 379 documents
Tumorigenic conversion of endothelial cells.
2003
Tumors of endothelial origin develop rarely. Until now, only two angiosarcoma (AS)-derived endothelial cell lines have been be isolated, ISO-HAS and AS-M. Both AS-derived endothelial cell lines presented the typical endothelial characteristics, such as the expression of CD31 and von Willebrand factor, but differed from normal endothelial cells in a nuclear expression of p53, in a delayed angiogenic reaction, and a reduced expression of caveolin. In addition, differences in the expression of cytokines and cell adhesion molecules responsive to proinflammatory stimuli were observed. While AS-M showed an expression pattern similar to that of human umbilical vein endothelial cells (HUVEC), ISO-H…
The dynamic properties of neuronal chromatin are modulated by triiodothyronine.
1992
The effect of triiodothyronine (T3) on the rate of synthesis of nuclear proteins was studied during terminal differentiation of rat cortical neurons cultured in a serum-free medium. To this aim total and acid soluble nuclear proteins were analyzed by different electrophoretic techniques. Our results show that: 1) during maturation in vitro, neuronal nuclei undergo a dramatic change in the rate at which different classes of histones and high mobility group (HMG) proteins are synthesized; the synthetic activity, measured as incorporation of radioactive precursors into nuclear proteins, slows indeed down with age: especially evident is the decrease in core histones synthesis; at day 15, on the…
Mid-region parathyroid hormone-related protein (PTHrP) binds chromatin of MDA-MB231 breast cancer cells and isolated oligonucleotides “in vitro”
2006
We have previously shown that PTHrP(38-94)-amide restrains growth and invasion "in vitro", causes striking toxicity and accelerates death of some breast cancer cell lines, the most responsive being MDA-MB231 whose tumorigenesis was also attenuated "in vivo". PTHrP(38-94)-amide contains the domain implicated in the nuclear import of PTHrP. Although the nucleus was identified as a destination for mid-region PTHrP, evidence for direct DNA-binding capability is lacking to date. Here, we examined the localization of PTHrP(38-94)-amide within MDA-MB231 cells and within metaphase spread preparations and characterized its DNA-binding properties, employing a combination of immunocytochemical, cytoge…
Hepatitis C Virus Core Protein Inhibits Tumor Suppressor Protein Promyelocytic Leukemia Function in Human Hepatoma Cells
2005
Abstract Tumor suppressor protein promyelocytic leukemia (PML) is implicated in apoptosis regulation and antiviral response. PML localizes predominantly to PML-nuclear bodies (PML-NB), nuclear macromolecular complexes regulating tumor suppressor protein p53 activity. Consistent with the function of PML in the cellular antiviral response, PML-NBs represent preferential targets in viral infections. In the case of hepatitis C virus (HCV) infection, important characteristics are nonresponsiveness to IFN therapy and development of hepatocellular carcinoma. However, the mechanisms which lead to the development of hepatocellular carcinoma are largely unknown. Here, we show that HCV core protein lo…
Oligodendroglioma cells synthesize the differentiation-specific linker histone H1˚ and release it into the extracellular environment through shed ves…
2013
Chromatin remodelling can be involved in some of the epigenetic modifications found in tumor cells. One of the mechanisms at the basis of chromatin dynamics is likely to be synthesis and incorporation of replacement histone variants, such as the H1° linker histone. Regulation of the expression of this protein can thus be critical in tumorigenesis. In developing brain, H1° expression is mainly regulated at the post-transcriptional level and RNA-binding proteins (RBPs) are involved. In the past, attention mainly focused on the whole brain or isolated neurons and little information is available on H1° expression in other brain cells. Even less is known relating to tumor glial cells. In this st…
Involvement of protein kinase Cdelta in contact-dependent inhibition of growth in human and murine fibroblasts.
2001
There is evidence that protein kinase C delta (PKCdelta) is a tumor suppressor, although its physiological role has not been elucidated so far. Since important anti-proliferative signals are mediated by cell-cell contacts we studied whether PKCdelta is involved in contact-dependent inhibition of growth in human (FH109) and murine (NIH3T3) fibroblasts. Cell-cell contacts were imitated by the addition of glutardialdehyde-fixed cells to sparsely seeded fibroblasts. Downregulation of the PKC isoforms alpha, delta, epsilon, and mu after prolonged treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA, 0.1 microM) resulted in a significant release from contact-inhibition in FH109 cells. Bryosta…
Pharmacologic activation of p53 elicits Bax-dependent apoptosis in the absence of transcription
2003
AbstractRecent efforts to develop pharmacologic agents that restore function to mutant forms of p53 hold significant promise in cancer therapy. Here, we examine the effects of such pharmacologic activation of p53 function using a small molecule, PRIMA-1, and a model system employing a p53 protein fused to a mutant steroid binding domain of the murine estrogen receptor (p53ERtam) that renders it responsive only in the presence of 4-hydroxytamoxifen. In either case, p53 activation triggered apoptosis that was not inhibited by the presence of macromolecular synthesis inhibitors. This p53-induced, transcription-independent apoptosis is Bax dependent, proceeds in the absence of a nucleus, and in…
Spatial regulation of the Start repressor Whi5
2009
The Saccharomyces cerevisiae Start repressor Whi5, the functional analogue of mammalian pRB, shuttles between the nucleus and the cytoplasm throughout the cell cycle: enters into the nucleus at the end of mitosis and remains nuclear until Start. We studied the mechanisms involved in this spatial regulation. The nuclear import depends on the beta-karyopherins of the classical import pathway Kap95 and Cse1. Whi5 contains a monopartite and a bipartite classical NLS localized in its N-terminal region which are functionally redundant. A fragment of Whi5 containing these NLSs is able to constitutively accumulate a GFP(4) protein inside the nucleus throughout the cell cycle, which suggests that th…
Cargo transport through the nuclear pore complex at a glance.
2021
ABSTRACT Bidirectional transport of macromolecules across the nuclear envelope is a hallmark of eukaryotic cells, in which the genetic material is compartmentalized inside the nucleus. The nuclear pore complex (NPC) is the major gateway to the nucleus and it regulates nucleocytoplasmic transport, which is key to processes including transcriptional regulation and cell cycle control. Accordingly, components of the nuclear transport machinery are often found to be dysregulated or hijacked in diseases. In this Cell Science at a Glance article and accompanying poster, we provide an overview of our current understanding of cargo transport through the NPC, from the basic transport signals and mach…
Survivin’s Dual Role: An Export’s View
2007
Survivin is proposed to function as a mitotic regulator and an apoptosis inhibitor during development and pathogenesis. As such, survivin has aroused keen interest in disparate areas of basic and translational research. Survivin acts as a subunit of the chromosomal passenger complex (CPC), composed of the mitotic kinase Aurora-B, Borealin and INCENP, and is essential for proper chromosome segregation and cytokinesis. Our recent findings indicate that the nuclear export receptor Crm1 is critically involved in tethering the CPC to the centromere by interacting with a leucine-rich nuclear export signal (NES), evolutionary conserved in all mammalian survivin proteins. In addition, the survivin/…