Search results for "Cell Nucleus"
showing 10 items of 379 documents
Human inducible nitric oxide synthase (iNOS) expression depends on chromosome region maintenance 1 (CRM1)- and eukaryotic translation initiation fact…
2012
Human inducible nitric oxide synthase (iNOS) is regulated on the expressional level mostly by post-transcriptional mechanisms modulating the mRNA stability. Another important step in the control of eukaryotic gene expression is the nucleocytoplasmic mRNA transport. Most cellular mRNAs are exported via the TAP/Nxt complex of proteins. However, some mRNAs are transported by a different mechanism involving the nuclear export receptor CRM1. Treatment of DLD-1 cells with the CRM1 inhibitor leptomycin B (LMB) or anti-CRM1 siRNAs reduced cytokine-induced iNOS expression. We could demonstrate that the iNOS mRNA is exported from the nucleus in a CRM1-dependent manner. Since CRM1 itself does not poss…
Association of AUUUA-binding Protein with A + U-rich mRNA during nucleo-cytoplasmic transport
1992
Resealed nuclear envelope (NE) vesicles from rat liver containing entrapped exogenous RNA were used to study the effect of adenosine+uridine binding factor (AUBF), present in cytosolic cell extracts, on ATP-dependent transport of A+U-rich RNA (AU+RNA) and A+U-free RNA (AU-RNA) across the NE. This factor specifically binds to A+U-rich sequences present in the 3' untranslated regions of lymphokine and cytokine mRNAs, containing overlapping AUUUA boxes (granulocyte-macrophage colony stimulating factor, interleukin-3). Addition of AUBF to the extravesicular compartment markedly increased the efflux of the in vitro transcribed, capped and polyadenylated AU+ RNAs. Export of entrapped AU- control …
3'-Untranslated regions of oxidative phosphorylation mRNAs function in vivo, as enhancers of translation
2000
Recent findings have indicated that the 3´-untranslated region (3´-UTR) of the mRNA encoding the β-catalytic subunit of the mitochondrial H+-ATP synthase has an in vitro translation-enhancing activity (TEA) [Izquierdo and Cuezva, Mol. Cell. Biol. (1997) 17, 5255–5268; Izquierdo and Cuezva, Biochem. J. (2000) 346, 849–855]. In the present work, we have expressed chimaeric plasmids that encode mRNA variants of green fluorescent protein in normal rat kidney and liver clone 9 cells to determine whether the 3´-UTRs of nuclear-encoded mRNAs involved in the biogenesis of mitochondria have an intrinsic TEA. TEA is found in the 3´-UTR of the mRNAs encoding the α- and β-subunits of the rat H+-ATP syn…
PML nuclear body-residing proteins sequentially associate with HPV genome after infectious nuclear delivery.
2019
Subnuclear promyelocytic leukemia (PML) nuclear bodies (NBs) are targeted by many DNA viruses after nuclear delivery. PML protein is essential for formation of PML NBs. Sp100 and Small Ubiquitin-Like Modifier (SUMO) are also permanently residing within PML NBs. Often, large DNA viruses disassemble and reorganize PML NBs to counteract their intrinsic antiviral activity and support establishment of infection. However, human papillomavirus (HPV) requires PML protein to retain incoming viral DNA in the nucleus for subsequent efficient transcription. In contrast, Sp100 was identified as a restriction factor for HPV. These findings suggested that PML NBs are important regulators of early stages o…
Cytoplasmic Parvovirus Capsids Recruit Importin Beta for Nuclear Delivery
2019
Parvoviruses are an important platform for gene and cancer therapy. Their cell entry and the following steps, including nuclear import, are inefficient, limiting their use in therapeutic applications. Two models exist on parvoviral nuclear entry: the classical import of the viral capsid using nuclear transport receptors of the importin (karyopherin) family or the direct attachment of the capsid to the nuclear pore complex leading to the local disintegration of the nuclear envelope. Here, by laser scanning confocal microscopy and in situ proximity ligation analyses combined with coimmunoprecipitation, we show that infection requires importin β-mediated access to the nuclear pore complex and …
A Protein Nuclear Extract fromD. melanogasterLarval Tissues
2008
Preparation of protein nuclear extracts is often the first step to study in vitro biological processes occurring in the nucleus of the eukaryotic cell. Nuclear extracts have been extensively used in different model organisms to identify and study protein function in nuclei. Drosophila embryos can be collected in large quantities and have been the source of choice for the production of protein nuclear extracts. However, most of Drosophila in vivo studies on protein function are conducted in larval tissues. Here we report a new method to produce highly stable large-scale protein nuclear extracts from whole Drosophila larvae that are suited for a variety of biochemical analyses.
Novel Insights into the Cellular Localization and Regulation of the Autophagosomal Proteins LC3A, LC3B and LC3C
2020
Macroautophagy is a conserved degradative process for maintaining cellular homeostasis and plays a key role in aging and various human disorders. The microtubule-associated protein 1A/1B light chain 3B (MAP1LC3B or LC3B) is commonly analyzed as a key marker for autophagosomes and as a proxy for autophagic flux. Three paralogues of the LC3 gene exist in humans: LC3A, LC3B and LC3C. The molecular function, regulation and cellular localization of LC3A and LC3C have not been investigated frequently, even if a similar function to that described for LC3B appears likely. Here, we have selectively decapacitated LC3B by three separate strategies in primary human fibroblasts and analyzed the evoked e…
The increase in maternal expression of axin1 and axin2 contribute to the zebrafish mutant ichabod ventralized phenotype.
2014
β-Catenin is a central effector of the Wnt pathway and one of the players in Ca(+)-dependent cell-cell adhesion. While many wnts are present and expressed in vertebrates, only one β-catenin exists in the majority of the organisms. One intriguing exception is zebrafish that carries two genes for β-catenin. The maternal recessive mutation ichabod presents very low levels of β-catenin2 that in turn affects dorsal axis formation, suggesting that β-catenin1 is incapable to compensate for β-catenin2 loss and raising the question of whether these two β-catenins may have differential roles during early axis specification. Here we identify a specific antibody that can discriminate selectively for β-…
Nuclear calcium signaling: An emerging topic in plants
2011
International audience; The calcium ion is probably one of the most studied second messenger both in plant and animal fields. A large number of reviews have browsed the diversity of cytosolic calcium signatures and evaluated their pleiotropic roles in plant and animal cells. In the recent years, an increasing number of reviews has focused on nuclear calcium, especially on the possible roles of nuclear calcium concentration variations on nuclear activities. Experiments initially performed on animal cells gave conflicting results that brought about a controversy about the ability of the nucleus to generate its own calcium signals and to regulate its calcium level. But in plant cells, several …
Genetic and Molecular Characterization of The Human Osteosarcoma 3AB-OS Cancer Stem Cell Line: A Possible Model For Studying Osteosarcoma Origin and …
2013
Finding new treatments targeting cancer stem cells (CSCs) within a tumor seems to be critical to halt cancer and improve patient survival. Osteosarcoma is an aggressive tumor affecting adolescents, for which there is no second-line chemotherapy. Uncovering new molecular mechanisms underlying the development of osteosarcoma and origin of CSCs is crucial to identify new possible therapeutic strategies. Here, we aimed to characterize genetically and molecularly the human osteosarcoma 3AB-OS CSC line, previously selected from MG63 cells and which proved to have both in vitro and in vivo features of CSCs. Classic cytogenetic studies demonstrated that 3AB-OS cells have hypertriploid karyotype wit…