Search results for "Core protein"
showing 10 items of 26 documents
DNA Hypomethylation and Histone Variant macroH2A1 Synergistically Attenuate Chemotherapy-Induced Senescence to Promote Hepatocellular Carcinoma Progr…
2016
Abstract Aging is a major risk factor for progression of liver diseases to hepatocellular carcinoma (HCC). Cellular senescence contributes to age-related tissue dysfunction, but the epigenetic basis underlying drug-induced senescence remains unclear. macroH2A1, a variant of histone H2A, is a marker of senescence-associated heterochromatic foci that synergizes with DNA methylation to silence tumor-suppressor genes in human fibroblasts. In this study, we investigated the relationship between macroH2A1 splice variants, macroH2A1.1 and macroH2A1.2, and liver carcinogenesis. We found that protein levels of both macroH2A1 isoforms were increased in the livers of very elderly rodents and humans, a…
TET3 prevents terminal differentiation of adult NSCs by a non-catalytic action at Snrpn.
2019
Ten-eleven-translocation (TET) proteins catalyze DNA hydroxylation, playing an important role in demethylation of DNA in mammals. Remarkably, although hydroxymethylation levels are high in the mouse brain, the potential role of TET proteins in adult neurogenesis is unknown. We show here that a non-catalytic action of TET3 is essentially required for the maintenance of the neural stem cell (NSC) pool in the adult subventricular zone (SVZ) niche by preventing premature differentiation of NSCs into non-neurogenic astrocytes. This occurs through direct binding of TET3 to the paternal transcribed allele of the imprinted gene Small nuclear ribonucleoprotein-associated polypeptide N (Snrpn), contr…
Hepatitis C virus-specific T-cell-derived transforming growth factor beta is associated with slow hepatic fibrogenesis.
2011
Up to 4 million persons in the USA have chronic hepatitis C (CHC) (1). Despite a decline in overall HCV infections, the number of patients with end stage liver disease due to CHC will increase for the next 2 decades (2). Even with highly effective novel therapies, currently 30–50% of infected individuals fail treatment (3). Therefore, a better understanding of mechanisms involved in CHC-related liver disease progression could permit more efficient therapies. Adaptive effector T cells (frequently assessed by measuring production of prototypic T helper 1 cytokine IFNγ) play an important role in control of HCV infection during the acute phase (4). In CHC, effector HCV-specific T cell immune re…
Free and antibody-complexed antigen and antibody profile in apparently healthy HIV seropositive individuals and in AIDS patients.
1990
The pattern of free and antibody-complexed HIV antigen and the antibody profile were investigated retrospectively in 305 serum samples taken from 22 AIDS patients before and during the development of AIDS and from 40 apparently healthy seropositive individuals. Most AIDS patients were found positive for both free and complexed antigen and had high gp41 antibody titres but low or undetectable p24 antibody. Four different patterns of HIV antigenaemia were observed: 1) positive for both free and complexed antigen; 2) negative for free HIV antigen at first, but always positive for complexed antigen; 3) positive for free antigen without complexed antigen; and 4) negative for both free and comple…
Virological profiles in patients with chronic hepatitis C and overt or occult HBV infection
2002
Abstract OBJECTIVES: The virological profiles of hepatitis B and C viruses (HBV and HCV) and their interplay in cases of coinfection are undefined. A suppressed and occult HBV infection may occur in hepatitis B surface antigen (HBsAg) negative patients with chronic hepatitis C. The HCV core protein is able to inhibit HBV “in vitro,” and serines at positions 99 and 116 are essential for such inhibition. We aimed to assess the HBV and HCV virological profiles in cases of coinfection and to evaluate the relationship between HCV core gene variability and HBV activity. METHODS: Eighty-two anti-HCV positive patients were examined: 35 cases were HBsAg positive, 24 were HBsAg negative with “occult”…
Maturation of IgG avidity to individual rubella virus structural proteins.
2001
Background: the structural proteins of rubella virus, the capsid protein C and the envelope glycoproteins E1 and E2 were produced in lepidopteran insect cells using baculovirus expression vectors. The C-terminal ends of the corresponding proteins were fused to a polyhistidine tag for easy and gentle purification by metal ion affinity chromatography. Objectives: to investigate the maturation of natural and vaccinal IgG avidity against individual authentic and recombinant rubella virus (RV) structural proteins. Study design the analysis was carried out using a modified immunoblotting technique where the purified baculovirus-expressed proteins were compared with authentic rubella virus protein…
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…
Upregulation of Major Histocompatibility Complex Class I on Liver Cells by Hepatitis C Virus Core Protein via p53 and TAP1 Impairs Natural Killer Cel…
2003
ABSTRACTThe mechanisms of immune evasion and the role of the early immune response in chronic infection caused by hepatitis C virus (HCV) are still unclear. Here, we present evidence for a cascade of molecular events that the virus initiates to subvert the innate immune attack. The HCV core protein induced p53-dependent gene expression of TAP1 (transporter associated with antigen processing 1) and consecutive major histocompatibility complex (MHC) class I upregulation. Moreover, in p53-deficient liver cell lines, only reconstitution with wild-type p53, but not mutated p53 lacking DNA binding capacity, showed this effect. As a consequence of increased MHC class I expression, a significantly …
DNA integrity, growth pattern, spindle formation, chromosomal constitution and imprinting patterns of mouse oocytes from vitrified pre-antral follicl…
2010
Cryopreservation of follicles for culture and oocyte growth and maturation in vitro provides an option to increase the number of fertilizable oocytes and restore fertility in cases where transplantation of ovarian tissue poses a risk for malignant cell contamination. Vitrification for cryopreservation is fast and avoids ice crystal formation. However, the influences of exposure to high concentrations of cryoprotectants on follicle development, oocyte growth and maturation, and particularly, on the DNA integrity and methylation imprinting has not been studied systematically. Follicle survival and development, DNA damage, oocyte growth patterns, maturation, spindle formation and chromosomal c…
Quantification of CD8+ T lymphocytes responsive to human immunodeficiency virus (HIV) peptide antigens in HIV-infected patients and seronegative pers…
1998
/ T cells responding to HIV-1 peptides were observed in none of 11 HIV- seronegative donors without a history of HIV exposure. ELISPOT assays are relatively fast and easy to perform and appear to reliably detect T cell reactivity due to previous exposure to HIV. These findings support the use of the ELISPOT assay for monitoring T cell responsiveness to HIV peptides. In acute infection with the human immunodeficiency virus We described recently an enzyme-linked immunospot (ELISPOT) assay to detect and quantitate single blood-de- type 1 (HIV-1), initial reduction in virus load is associated with the appearance of a high frequency of antiviral cytotoxic T rived CD8 / T lymphocytes forming tumo…