Search results for "Viruses"
showing 10 items of 1182 documents
Synergism between the components of the bipartite major immediate-early transcriptional enhancer of murine cytomegalovirus does not accelerate virus …
2009
Major immediate-early (MIE) transcriptional enhancers of cytomegaloviruses are key regulators that are regarded as determinants of virus replicative fitness and pathogenicity. The MIE locus of murine cytomegalovirus (mCMV) shows bidirectional gene-pair architecture, with a bipartite enhancer flanked by divergent core promoters. Here, we have constructed recombinant viruses mCMV-ΔEnh1 and mCMV-ΔEnh2 to study the impact of either enhancer component on bidirectional MIE gene transcription and on virus replication in cell culture and various host tissues that are relevant to CMV disease. The data revealed that the two unipartite enhancers can operate independently, but synergize in enhancing MI…
Inhibition of human T-cell leukemia virus type I replication in primary human T cells that express antisense RNA
1989
The human T-cell leukemia virus type I is associated with adult T-cell leukemia-lymphoma in humans, a disease which is induced by a malignant transformation of T lymphocytes. Retrovirus vectors carrying human T-cell leukemia virus type I-derived sequences in reversed transcriptional orientation were used to express antisense RNA transcripts in primary human leukocytes. Human T-cell leukemia virus type I replication and virus-mediated immortalization were inhibited in cells harboring antisense constructs. This study suggests that retrovirus-mediated antisense RNA inhibition can be used to protect primary human T-lymphocytes from human T-cell leukemia virus type I-mediated cell transformation.
Inhibitors acting on nucleic acid synthesis in an oncogenic RNA virus.
1971
IN infection with an oncogenic RNA virus, synthesis of viral RNA seems to be catalysed by an RNA dependent DNA polymerase in the host cell1–4. Several specific inhibitors of viral DNA polymerases have been found5–7 and Spiegelman8 has shown that the activity of viral enzymes depends strongly on the chemical composition of the template. We report here first a new highly specific poison of the Rauscher murine leukaemia virus (RMLV) DNA polymerases; second, several inactivators of the RNA and DNA template involved in the RMLV enzyme systems; and third, the action of actinomycin D on viral DNA polymerases and on host DNA/RNA polymerase. The results are discussed with respect to the influence of…
Improvement of baculovirus as protein expression vector and as biopesticide by CRISPR/Cas9 editing
2019
The clustered regularly interspaced short palindromic repeats (CRISPR) system?associated Cas9 endonuclease is a molecular tool that enables specific sequence editing with high efficiency. In this study, we have explored the use of CRISPR/Cas9 system for the engineering of baculovirus. We have shown that the delivering of Cas9-single guide RNA ribonucleoprotein (RNP) complex with or without DNA repair template into Sf21 insect cells through lipofection might be efficient to produce knockouts as well as knock-ins into the baculovirus. To evaluate potential application of our CRISPR/Cas9 method to improve baculovirus as protein expression vector and as biopesticide, we attempted to knockout se…
Nuclear expression of apurinic/apyrimidinic endonuclease increases with progression of ovarian carcinomas.
2003
Apurinic/apyrimidinic endonuclease (APE alias Ref-1) is a key enzyme in the base excision repair pathway. Besides its function in DNA repair, APE serves to maintain several transcription factors in an active reduced state such as c-Fos, c-Jun, NF-kappaB, p53 and HIF-1alpha, all of which have been shown to play a role in tumorigenesis. Because of the importance of APE in maintaining genomic stability and gene regulation, we examined whether APE expression is associated with survival and histopathological parameters of patients with ovarian cancer.Tissue sections of primary epithelial ovarian carcinomas from 141 patients were immunostained using a monoclonal antibody directed against APE.Nucl…
Molecular Characterization of Virus-induced Autoantibody Responses
2004
Here we present a comprehensive molecular mapping of virus-induced autoimmune B cell responses obtained by serological identification of antigens by recombinant expression cloning analysis. Immunoscreening of cDNA expression libraries of various organs (lung, liver, and spleen) using sera from mice infected with cytopathic (vaccinia virus [VV]) or noncytopathic (lymphocytic choriomeningitis virus [LCMV]) viruses revealed a broad specificity of the elicited autoantibody response. Interestingly, the majority of the identified autoantigens have been previously described as autoantigens in humans. We found that induction of virus-induced autoantibodies of the immunoglobulin G class largely depe…
Structure of SNX9 SH3 in complex with a viral ligand reveals the molecular basis of its unique specificity for alanine-containing class I SH3 motifs
2021
Class I SH3 domain-binding motifs generally comply with the consensus sequence [R/K]x0PxxP, the hydrophobic residue 0 being proline or leucine. We have studied the unusual 0 = Ala-specificity of SNX9 SH3 by determining its complex structure with a peptide present in eastern equine encephalitis virus (EEEV) nsP3. The structure revealed the length and composition of the n-Src loop as important factors determining specificity. We also compared the affinities of EEEV nsP3 peptide, its mutants, and cellular ligands to SNX9 SH3. These data suggest that nsP3 has evolved to minimize reduction of conformational entropy upon binding, hence acquiring stronger affinity, enabling takeover of SNX9. The R…
Increase in norovirus activity reported in Europe.
2006
A large increase in norovirus outbreaks in Hungary and Germany was reported to European national health authorities via the Foodborne Viruses in Europe network
Suppression of humoral immune response against herpes simplex virus induced by defective strains, ts- and TK- mutants.
1988
Suppression of humoral antibody formation against HSV is not only induced by replicating Herpes simplex virus type 2 (HSV-2) but also by the defective strain ANG and the deletion mutant 1301 of Herpes simplex virus type 1 (HSV-1). Moreover, ts-mutants A, H, K, S, 1201 and 1208 of HSV-1 as well as some ts-mutants of HSV-2 and “defective-interfering” particles of HSV-1 after high multiplicity of infection-passages induced suppression. Treatment of infected mice with ACG reduced antibody-formation but did not result in suppression. UV-irradiation of the antibody producing strain Len of HSV-1 strongly reduces antibody formation and induces suppression. Experiments using a series of intertypic r…
Assembly of the Major and the Minor Capsid Protein of Human Papillomavirus Type 33 into Virus-like Particles and Tubular Structures in Insect Cells
1994
Native virions of human papillomaviruses (HPV) can be isolated from genital lesions only in very limited amounts. Recent studies have shown that virus-like particles can be obtained by expression of the capsid proteins using vaccinia virus recombinants or the baculovirus system. We now present the first detailed characterization of virus-like particles of a human papillomavirus associated with malignant genital lesions, HPV-33, produced in high yield using the baculovirus expression system. Assembly of the major capsid protein L1 alone or together with the minor capsid protein L2 has been obtained. Both spherical virus-like particles of 50-60 nm diameter and tubular structures of either 25-…