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DNA replication of phage-plasmid P4 proceeds bidirectionally from theori1site (previously namedori), but requires a secondcis-acting region,crr.Replication depends on the product of the P4 α gene, a protein with primase and helicase activity, that binds bothori1andcrr.A negative regulator of P4 DNA replication, the Cnr protein, is required for copy number control of plasmid P4. Using a plasmid complementation...
Prior genetic analysis suggests that there may exist an interaction between the products of the vaccinia virus genes A18R, a putative negative transcription elongation factor, and G2R, a putative positive transcription elongation factor. In addition, affinity purification of polyhistidine-tagged G2R protein overexpressed in vaccinia virus-infected cells, reported here, results in copurification of...
Deng and Shuman (J. Biol Chem.271, 29386 (1996)) reported that an ATPase different from the known viral termination factor, VTF, is required for vaccinia virus early gene transcription termination. Properties of this ATPase were similar to those of a known vaccinia virus enzyme, nucleoside triphosphate phosphohydrolase I (NPH I) the product of gene D11L. Transcription-competent cell-free extracts...
Yeast two-hybrid selection of proteins interacting with human immunodeficiency virus type 1 Vpr identified HHR23A, a human homologue of the yeast DNA repair protein RAD23, as a specific interactor. A small 57-amino-acid C-terminal portion of HHR23A was sufficient for Vpr interaction. When introduced into human cells by transfection, full-length HHR23A or its C-terminal fragments were able to alleviate...
The HIV-1 Vpr protein is a virion-associated protein which has been shown to facilitate infection of nondividing macrophages and additionally to alter cell cycle and proliferation status of the infected host cell. HIV-1 Vpr also was recently shown to associate with the DNA repair enzyme uracil DNA glycosylase (UDG). This association with a DNA repair enzyme is intriguing given that nonprimate lentiviruses...
Using a series of modified wtSV40 and early region SV40 DNAs, we assayed the effect of viral late region sequences on T-antigen production by the SV40 early region. We found that SV40 late region (L-SV40) DNA sequences reduced T-antigen (T-Ag) production by the SV40 early region (E-SV40) when both viral regions were linked as they are in wtSV40 DNA. This was demonstrated by Western analysis which...
The virus-associated VAI RNA of adenovirus is a small highly structured RNA that is required for the efficient translation of cellular and viral mRNAs at late times after infection. VAI RNA antagonizes the activation of the interferon-inducible RNA-dependent protein kinase, PKR, an important regulator of translation. The RNA-specific adenosine deaminase, ADAR, is an interferon-inducible RNA-editing...
Interleukin 10 (IL-10) is an important anti-inflammatory cytokine. To examine its role in virus-induced encephalomyelitis, IL-10-deficient (IL-10 −/−) mice were infected with a neurotropic strain of mouse hepatitis virus (JHMV). JHMV-infected IL-10 −/− mice, compared to IL-4 −/− and syngeneic C57BL/6 mice, exhibited increased morbidity and mortality. Virus was cleared from the CNS of all groups of...
Previous studies have shown that mouse adenovirus type-1 (MAV-1) caused a fatal hemorrhagic encephalitis in certain strains of mice. C57Bl/6 mice exhibited 100% mortality when given as little 10 3 plaque-forming units (PFU) of MAV, in contrast to BALB/c mice which were resistant to as many as 10 6 PFU. Susceptible animals died with a flaccid paralysis on the 3rd or 4th day after inoculation...
The molecular chaperone cyclophilin A (Cyp A) modulates human immunodeficiency virus type 1 (HIV-1) infectivity through its interactions with Gag structural proteins. The molecular mechanism for CypA in HIV-1 replication is not known. We studied chaperone effects on Gag precursor processing using cyclosporin A (CsA) to bind CypA and prevent its interaction with p55 Gag . CsA treatment inhibited...
Human enteroviruses and rhinoviruses rapidly and selectively abolish translation from cellular mRNA upon infection of susceptible cells. Expression of the poliovirus 2A protease (PV 2A pro ) is sufficient to cause host translation shutoff through cleavage of eIF4G (formerly p220, eIF4γ) either directly or indirectly through activation of a cellular factor. Evidence exists for both direct and...
Sporozoites of the protozoan parasite,Cryptosporidium parvum,were found to contain free, full-size plus strands transcribed from two extrachromosomal, cytoplasmic, virus-like double-stranded RNAs (dsRNAs). Cell-free transcription and replication of both dsRNAs were observed in crude sporozoite lysates. RNA polymerase activity was found to be dependent upon addition of Mg 2+ or Mn 2+ ...
Previously, the purified recombinant 2A proteases (2A pro ) of coxsackievirus B4 (CVB4) and human rhinovirus type 2 (HRV2) were shown to cleave synthetic peptides derived from human or rabbit eIF4G as well as eIF4G protein purified from rabbit reticulocytes. These results were in contrast to previous evidence which supported the view that eIF4G cleavage activity in poliovirus-infected HeLa...
The Sabin vaccine strains of poliovirus, like all RNA viruses, exist as a quasispecies of genomic sequences whose composition can be altered during virus propagation. Since changes in vaccine virus during manufacture can enhance the neurovirulent potential of the vaccine, each monovalent lot of oral poliovirus vaccine (OPV) undergoes several tests to ensure consistency of manufacture, including the...
Mason–Pfizer monkey virus (M-PMV) proteinase, released by the autocatalytic cleavage of Gag-Pro and Gag-Pro-Pol polypeptide precursors, catalyzes the processing of viral precursors to yield the structural proteins and enzymes of the virion. In retroviruses, usually only one proteolytically active form of proteinase exists. Here, we describe an unusual feature of M-PMV, the existence of three active...
In a previous study on the replication of Kunjin virus using immunoelectron microscopy (E. G. Westaway, J. M. Mackenzie, M. T. Kenney, M. K. Jones, and A. A. Khromykh, 1997,J. Virol.71, 6650–6661), NS1 and NS3 were found associated with double-stranded RNA (dsRNA) within vesicle packets (VP) in infected Vero cells, suggesting that these induced membrane structures may be the cytoplasmic sites of RNA...
Mapping and possible diagnostic meaning of a highly conserved, linear NS4 epitope (NS4/3), located outside the C100-3 antigen within the carboxyl terminal proportion of the NS4 region, with major immunoreactivity with specimens of patients with HCV infection from various geographic origins is described. Transient, acute-phase IgM anti-HCV NS4/3 was detected coincidentally or earlier than active IgG...
We used human papillomavirus type 16 (HPV-16) particles composed of capsid proteins L1 and L2 (L1/L2 capsids) as an antigen to produce mouse monoclonal antibodies (MAbs). Of 18 MAbs recognizing surface epitopes of L1/L2 capsids, 1 was an anti-L1 MAb and 17 were anti-L2 MAbs. Seven of 11 anti-L2 MAbs recognizing linear epitopes were found to bind to a synthetic peptide with an HPV-16 L2 sequence of...
In a previous report, we showed that proteolytic processing of an 87-kDa mature viral protein from the coronavirus infectious bronchitis virus (IBV) 1a and 1a/1b polyproteins was mediated by two putative overlapping papain-like proteinase domains (PLPDs) encoded within the region from nucleotides 4243 to 5553 of ORF 1a (Liuet al.,1995). In this study, we demonstrate that only the first domain, PLPD-1,...
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