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Retroviruses are used for a variety of applications requiring the delivery of exogenous genes to cells and animals. For many of these applications, including gene therapy, safer and more efficient retroviral vectors are needed. Vectors based on Harvey murine sarcoma virus (HaMSV) are attractive because nearly all their viral sequences outside of the LTRs are derived from rat endogenous VL30 retroviruses...
In contrast to the purely enhancer-dependent effect of cytokines such as TNF on the activity of the HIV regulatory region (LTR), we observed that okadaic acid (OKA) activates HIV transcription through both the enhancer, responding to the factor NF-κB, and the promoter domain of the LTR. The inducibility of HIV LTR-driven luciferase expression constructs in lymphoblastoid cells stimulated by OKA depended...
Aura virus is an alphavirus present in Brazil and Argentina that is serologically related to Sindbis virus (present throughout the Old World) and to Western equine encephalitis (WEE) virus (present in the Americas). We have previously shown that WEE is a recombinant virus whose glycoproteins and part of whose 3′ nontranslated region (NTR) are derived from a Sindbis-like virus, but the remainder of...
In a previous study, a mouse L cell mutant was isolated which is 90% resistant to HSV-1 infection (S. Gruenheid, L. Gatzke, H. Meadows, and F. Tufaro. J. Virol. 67, 93-100, 1993). This cell line, termed gro2C, failed to express heparan sulfate (HS) glycosaminoglycans on the cell surface, which normally act as initial receptors for HSV-1 attachment to cultured cells. In this report, we extended the...
Tobacco mosaic virus mutant PM2 contains two amino acid changes in coat protein sequence relative to the sequence of the coat protein of TMV U1. This results in unstable infectivity, inability to cause normal systemic infection, and accumulation of elongated open helixes of coat protein. Using site-directed mutagenesis we demonstrated that the characteristics of PM2 are due to the change of Thr28...
The sequence of the entire genome of citrus tristeza virus (CTV), Florida isolate T36, was completed. The 19,296-nt CTV genome encodes 12 open reading frames (ORFs) potentially coding for at least 17 protein products. The 5′-proximal ORF 1a starts at nucleotide 108 and encodes a large polyprotein with calculated MW of 349 kDa containing domains characteristic of (from 5′ to 3′) two papain-like proteases...
Bacterially expressed Epstein-Barr virus (EBV) DNase was purified to 98% purity and used as the source for characterization of the enzyme activities. Complete digestion of DNA by EBV DNase yielded 5′-monophosphate nucleosides as the final products. During the logarithmic phase of the reaction, EBV DNase acted processively on dsDNA but distributively on ssDNA. Both 5′ to 3′ and 3′ to 5′ exonuclease...
Human T-cell lymphotropic virus type I (HTLV-I) infection is typically associated with long incubation periods between virus exposure and disease manifestation. Although viral protein expression is considered to play an important role in the pathogenesis of HTLV-I-associated diseases, limited information is known regarding host cell mechanisms that control viral gene expression. This study was designed...
The biological functions of the structural protein σC, from avian reovirus strain RAM-l, were investigated in this study. A putative fusion peptide in σC was recognized in the deduced amino acid sequence by homology with Pneumovirus fusion sequences, and it was thus postulated that this protein may be involved in the formation of syncytia in cells infected with RAM-1. The σC gene was cloned and expressed...
Herpesvirus saimiri (H. saimiri) is a highly oncogenic lymphotropic herpesvirus which can immortalize T lymphocytes and cause tumors in rabbits and New World monkeys T cells infected with strain 484-77 of group C express four viral U-like small RNAs (HSUR1-4) and a 1.2-kb mRNA which encodes open reading frames ORF-1 and ORF-2. ORF-1 encodes a collagen-like oncoprotein. Deletion mutation analysis showed...
We investigated effects of site-specific mutation of the putative C/EBP binding site in the feline immunodeficiency virus (FIV) long terminal repeat (LTR) on the basal promoter activity in Crandell feline kidney (CRFK) cells and on replication efficiency in CRFK cells and a T-lymphoblastoid cell line, MYA-1 cells. Mutation of the C/EBP site reduced the basal promoter activity in CRFK cells and prevented...
Venezuelan equine encephalitis virus (VEE) causes a biphasic disease in mice following subcutaneous inoculation in the footpad. In the initial phase, virus replicates primarily in the lymphoid tissues and induces a high titer viremia. Subsequently, the virus invades the central nervous system (CNS) from the circulation, and an encephalitis ensues. At the earliest times that VEE specific in situ hybridization...
The v-myb oncogene causes monoblastic leukemia in chickens and transforms avian myelomonocytic cells in vitro. vMyb is a short-lived nuclear protein which binds to DNA in a sequence-specific manner and can activate gene expression in transient DNA transfections. Analysis of a series of v-Myb mutants has shown that the ability to activate transcription appears to be required for leukemic transformation...
Epstein-Barr virus (EBV) is known to infect B cells and epithelial cells. We and others have shown that EBV can also infect a subset of thymocytes. Infection of thymocytes was accompanied by the appearance of linear EBV genome within 8 hr of infection. Circularization of the EBV genome was not detected. This is in contrast to the infection in B cells where the genome can circularize within 24 hr of...
Early region 3 (E3) of mouse adenovirus type 1 produces three mRNAs that can encode three proteins with unique carboxy-terminal exons. A bacterial fusion protein encoding the unique terminus of one of the three predicted proteins was used to generate antiserum in rabbits. This antiserum detected a 14K protein on a Western blot of infected cell lysates. Immunoprecipitation and endoglycosidase H digestion...
Hepatitis C virus (HCV) RNA contains a highly conserved 5′-noncoding region (5′NCR) which may be important in viral multiplication. To study the possible mechanisms of the cellular proteins involved in HCV replication and pathogenesis, a gel mobility shift assay and competition analysis were performed with the HCV 5′NCR. Two specific complexes were formed between the 341-nucleotide RNA of the HCV...
It has been postulated that antibodies specific to the hypervariable region 1 (HVR1) within the putative envelope protein E2 of hepatitis C virus (HCV) can neutralize virus. We studied such antibodies in sera of patients who were infected in a single-source outbreak by a contaminated anti-D immunoglobulin preparation (HCV-AD78). The nucleotide sequences of cDNAs encoding HVR1 of HCV-AD78 were determined...
Several reports have been recently published concerning the identification of HBV variants due to rearrangements of the preS1/preS2 or core regions of the viral genome. To evaluate the frequency of the natural occurrence of such variants and whether the heterogeneity of these genomic regions correlates with the severity of the liver disease, we have examined the preS1/preS2 region and the entire core...
Because of the importance of the envelope glycoprotein (Env) in determining the pathogenicity of HIV-1 and the importance of the immune response to Env in controlling virus spread, attempts are being made to study HIV-1 Env-directed immunity in primate models. To date HIV-1 Env-specific effector T lymphocyte responses have not been demonstrated in virusinfected nonhuman primates. We have previously...
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