The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Irene Bozzoni - One of the best experts on this subject based on the ideXlab platform.
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Inhibition of Human Immunodeficiency Virus Type 1 Replication by Nuclear Chimeric Anti-HIV Ribozymes in a Human T Lymphoblastoid Cell Line
Human gene therapy, 1998Co-Authors: Alessandro Michienzi, Lucia Conti, Barbara Varano, Silvia Prislei, Sandra Gessani, Irene BozzoniAbstract:Human immunodeficiency virus (HIV) infection represents one of the most challenging systems for gene therapy. Thanks to the extended knowledge of the molecular biology of the HIV life cycle, many different strategies have been developed including transdominant modifications of HIV proteins, RNA decoys, antisense RNA, ribozymes, and intraCellular antibody fragments. In this paper, we have tested in a human T Lymphoblastoid Cell Line the antiviral activity of ribozymes specifically designed to co-localize inside the nucleus with the Rev pre-mRNA before it is spliced and transported to the cytoplasm. This result was obtained by inserting the ribozyme in the spliceosomal U1 small nuclear RNA (snRNA) and in a derivative that has perfect complementarity with the 5' splice site of the Rev pre-mRNA. These ribozymes were tested in human T Cell clones and were shown to be very efficient in inhibiting viral replication. Not only were the p24 levels in the culture medium drastically reduced but so were the intraCellular HIV transcripts. Control disabled ribozymes enabled us to show the specificity of the ribozyme activity. Therefore, these constructs have potential utility for gene therapy of HIV-1 infection.
Michael Fenech - One of the best experts on this subject based on the ideXlab platform.
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the effect of zinc sulphate and zinc carnosine on genome stability and cytotoxicity in the wil2 ns human Lymphoblastoid Cell Line
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2011Co-Authors: Razinah Sharif, Philip J Thomas, P D Zalewski, Robin D Graham, Michael FenechAbstract:Abstract Zinc (Zn) is an essential cofactor required by numerous enzymes that are essential for Cell metabolism and the maintenance of DNA integrity. We investigated the effect of Zn deficiency or excess on genomic instability events and determined the optimal concentration of two Zn compounds that minimize DNA-damage events. The effects of Zn sulphate (ZnSO4) and Zn carnosine (ZnC) on Cell proliferation were investigated in the WIL2-NS human Lymphoblastoid Cell Line. DNA damage was determined by the use of both the comet assay and the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. Zn-deficient medium (0 μM) was produced using Chelex treatment, and the two Zn compounds (i.e. ZnSO4 and ZnC) were tested at concentrations of 0.0, 0.4, 4.0, 16.0, 32.0 and 100.0 μM. Results from an MTT assay showed that Cell growth and viability were decreased in Zn-depleted Cells (0 μM) as well as at 32 μM and 100 μM for both Zn compounds (P
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the effect of zinc sulphate and zinc carnosine on genome stability and cytotoxicity in the wil2 ns human Lymphoblastoid Cell Line
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2011Co-Authors: Razinah Sharif, Philip J Thomas, P D Zalewski, Robin D Graham, Michael FenechAbstract:Zinc (Zn) is an essential cofactor required by numerous enzymes that are essential for Cell metabolism and the maintenance of DNA integrity. We investigated the effect of Zn deficiency or excess on genomic instability events and determined the optimal concentration of two Zn compounds that minimize DNA-damage events. The effects of Zn sulphate (ZnSO(4)) and Zn carnosine (ZnC) on Cell proliferation were investigated in the WIL2-NS human Lymphoblastoid Cell Line. DNA damage was determined by the use of both the comet assay and the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. Zn-deficient medium (0μM) was produced using Chelex treatment, and the two Zn compounds (i.e. ZnSO(4) and ZnC) were tested at concentrations of 0.0, 0.4, 4.0, 16.0, 32.0 and 100.0μM. Results from an MTT assay showed that Cell growth and viability were decreased in Zn-depleted Cells (0μM) as well as at 32μM and 100μM for both Zn compounds (P<0.0001). DNA strand-breaks, as measured by the comet assay, were found to be increased in Zn-depleted Cells compared with the other treatment groups (P<0.05). The CBMN-Cyt assay showed a significant increase in the frequency of both apoptotic and necrotic Cells under Zn-deficient conditions (P<0.0001). Elevated frequencies of micronuclei (MNi), nucleoplasmic bridges (NPBs) and nuclear buds (NBuds) were induced in Zn-depleted Cells (P<0.0001), whereas genome damage was reduced in supplemented cultures for both Zn compounds at 4μM and 16μM, possibly suggesting that these concentrations may be optimal for genome stability. The potential protective effect of ZnSO(4) and ZnC was also investigated following exposure to 1.0Gy γ-radiation. Culture in medium containing these compounds at 4-32μM prior to irradiation displayed significantly reduced frequencies of MNi, NPBs and NBuds compared with Cells maintained in 0μM medium (P<0.0001). Expression of γ-H2AX and 8-oxoguanine glycosylase measured by western blotting was increased in Zn-depleted Cells. These results suggest that Zn plays important role in genomic stability and that the optimal Zn concentration-range for prevention of DNA damage and cytotoxicity in vitro lies between 4 and 16μM.
Karel A Schat - One of the best experts on this subject based on the ideXlab platform.
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characterization of marek s disease virus bamhi a specific cdna clones obtained from a marek s disease Lymphoblastoid Cell Line
Virology, 1994Co-Authors: Kazuhiko Ohashi, P H Oconnell, Karel A SchatAbstract:Abstract A cDNA library was constructed from poly(A) + RNA fractions obtained from a Marek's disease (MD) Lymphoblastoid Cell Line, MDCC-CU41, in which viral gene expression is very limited. Three independent groups (1, 2, and 3) of MD virus (MDV)-specific clones were obtained, which were mapped in the inverted repeat region of the Bam HI-A fragment of the MDV genome. Northern blot analysis showed that probes prepared from these cDNA clones hybridized with several transcripts of different sizes in poly(A) + RNA of MDCC-CU41, although the amounts of these transcripts were relatively small compared to those in MDV lytically infected Cells. Moreover, a small open reading frame, which can encode a 94-amino-acid protein, was identified in the A41 cDNA clone (Group 3). By RNase protection assays, the 1.2-kb Group 3 transcriptional unit has been defined. In indirect immunofluorescent antibody assays, antiserum against the bacterially expressed fusion protein, glutathione S -transferase-A41, reacted specifically with the cytoplasmic regions of MDV (strain RB1B)-infected chick kidney Cells. However, MDCC-CU41 did not contain a detectable lever of the protein determined by these methods.
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characterization of a marek s disease virus bamhi l specific cdna clone obtained from a marek s disease Lymphoblastoid Cell Line
Journal of Virology, 1994Co-Authors: Kazuhiko Ohashi, Wenping Zhou, P H Oconnell, Karel A SchatAbstract:Two Marek's disease (MD) virus BamHI-L-specific cDNA clones were isolated from a cDNA library constructed from poly(A)+ RNA fractions of an MD Lymphoblastoid Cell Line, MDCC-CU41 (CU41). These clones were mapped to the region corresponding to the BamHI-Q2 and L-regions. These clones hybridized with 2.5-, 0.8-, and 0.6-kb transcripts prepared from CU41. The transcriptional unit of the 0.6-kb transcript was determined by RNase protection assays. An open reading frame encoding a 107-amino-acid polypeptide was identified in the 0.6-kb transcript. Reverse transcriptase-PCR demonstrated the presence of this transcript in both CU41 and a reticuloendotheliosis virus-transformed Cell Line latently infected with MD virus.
Hufeng Zhou - One of the best experts on this subject based on the ideXlab platform.
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epstein barr virus nuclear antigen leader protein localizes to promoters and enhancers with Cell transcription factors and ebna2
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Daniel Portal, Hufeng Zhou, Bo Zhao, Peter V Kharchenko, Elizabeth Lowry, Limsoon WongAbstract:Epstein–Barr virus (EBV) nuclear antigens EBNALP (LP) and EBNA2 (E2) are coexpressed in EBV-infected B lymphocytes and are critical for Lymphoblastoid Cell Line outgrowth. LP removes NCOR and RBPJ repressive complexes from promoters, enhancers, and matrix-associated deacetylase bodies, whereas E2 activates transcription from distal enhancers. LP ChIP-seq analyses identified 19,224 LP sites of which ∼50% were ±2 kb of a transcriptional start site. LP sites were enriched for B-Cell transcription factors (TFs), YY1, SP1, PAX5, BATF, IRF4, ETS1, RAD21, PU.1, CTCF, RBPJ, ZNF143, SMC3, NFκB, TBLR, and EBF. E2 sites were also highly enriched for LP-associated Cell TFs and were more highly occupied by RBPJ and EBF. LP sites were highly marked by H3K4me3, H3K27ac, H2Az, H3K9ac, RNAPII, and P300, indicative of activated transcription. LP sites were 29% colocalized with E2 (LP/E2). LP/E2 sites were more similar to LP than to E2 sites in associated Cell TFs, RNAPII, P300, and histone H3K4me3, H3K9ac, H3K27ac, and H2Az occupancy, and were more highly transcribed than LP or E2 sites. Gene affected by CTCF and LP cooccupancy were more highly expressed than genes affected by CTCF alone. LP was at myc enhancers and promoters and of MYC regulated ccnd2, 23 med complex components, and MYC regulated Cell survival genes, igf2r and bcl2. These data implicate LP and associated TFs and DNA looping factors CTCF, RAD21, SMC3, and YY1/INO80 chromatin-remodeling complexes in repressor depletion and gene activation necessary for Lymphoblastoid Cell Line growth and survival.
Bharat B Aggarwal - One of the best experts on this subject based on the ideXlab platform.
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human immunodeficiency virus type 1 tat gene up regulates interleukin 4 receptors on a human b Lymphoblastoid Cell Line
Cancer Research, 1992Co-Authors: Raj K Puri, Bharat B AggarwalAbstract:The human immunodeficiency virus type I (HIV-1) regulatory gene, tat III, is a powerful trans -activator of gene expression from the viral long terminal repeat and is essential for HIV replication. In addition, tat III protein has been shown to be immunosuppressive as indicated by the inhibition of antigen mediated T-Cell proliferation. To further test whether tat III might play a direct role in the immunosuppressive effects of HIV-1 in addition to its role in virus replication, we examined the regulation of interleukin 4 (IL-4) receptors on a human B-Lymphoblastoid Cell Line (Raji) transfected with HIV-1 tat gene (Raji- tat III). We used radioligand receptor binding analysis for Cell surface expression and Northern blot analysis for the expression of human IL-4 receptor gene in Raji- tat III Cells. Control Raji Cells expressed 1383 ± 361 (SE; n = 3) IL-4 binding sites/Cell with a dissociation constant ( Kd ) of 144 ± 27 pm ( n = 3). However, Raji- tat III Cells expressed about three times higher IL-4 receptors (4000 ± 633 IL-4 binding sites/Cell; P 0.05 compared to Raji Cells). Whereas both Raji and Raji- tat III Cells exhibited a single mRNA species (approximately 4 kilobases) of IL-4 receptors by Northern blot analysis, the mRNA level was about 3-fold higher in Raji- tat III Cells compared to Raji Cells. Cycloheximide inhibited the expression of IL-4 receptors by 50% in about 2 h in both Cell types indicating both the half-life of IL-4 receptors and the requirement for protein synthesis for the tat III up-regulation of IL-4 receptors. Since IL-4 under certain circumstances has been shown to be immunosuppressant, our observation that the HIV-1 tat gene up-regulates IL-4 receptors suggests the possibility that the immunosuppressive effects of HIV-1 are mediated at least in part through IL-4 receptors.
