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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is evidence that the nucleoprotein (NP) gene of the classical swine virus (A/Swine/1976/31) clusters with the early human strains at the nucleotide sequence level, while at the level of the amino acid sequence, as defined by consensus amino acids and in functional tests, its NP is clearly "avian like." Therefore it was suggested that the Sw/31 NP had been recently under strong selection pressure, possibly caused by reassortment with other avian influenza genes, whose gene products have to cooperate intimately with NP (Gammelin et al., 1989. Virology 170, 71-80). This suggestion has been investigated by sequencing the genes of internal and nonstructural proteins of Sw/31. The data on these sequences and on the phylogenetic trees are not in accordance with that suggestion: all these genes cluster with the early human strains at the nucleotide level while, at the level of the amino acid sequence, most of them are more closely related to the avian strains, thus resembling NP in this respect. This indicates that these genes rather evolved concomitantly with the NP gene. Our data are in agreement with the suggestion that, at about the time of the Spanish Flu (1918/19), a human influenza A (H1N1) virus entered the pig population. Furthermore, it is known that the NP of the human influenza A viruses--in contrast to that of the avian and swine strains--has been under strong selection pressure to change (Gammelin et al., 1990. Mol. Biol. Evol. 7, 194-200. Gorman et al., 1990a. J. Virol. 64, 1487-1497). Thus, after transfer of a human strain into pigs, the selection pressure might be released, enabling the NP and the other genes of the swine virus to evolve back to the optimal avian sequences, especially at the functionally important consensus positions. The swine influenza viruses circulating since 1979 in Northern Europe--represented by A/Swine/Germany/2/81 (H1N1)--have all genes, so far examined, derived from an avian influenza virus pool and are different from the classical swine viruses.
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PMID:Evolution of pig influenza viruses. 205 97

In order to determine how T cell-presented peptides associate with the antigen binding sites (desetopes) of class I major histocompatibility complex (MHC) molecules and how they might be scavenged from an endogenous processing pathway for transfer to those molecules, we characterized the binding of two synthetic peptides restricted by HLA-B37 or HLA-A2 to class I MHC molecules and to cellular proteins of histotyped cell lines, by gel filtration and photo-affinity labeling techniques. In gel filtration binding studies, each peptide associated with immunopurified class I MHC molecules from cells with its restricting, histotype, but little was bound to class I MHC molecules from cells without the restricting histotype and none was bound to bovine serum albumin. After crosslinkage of a radioiodinated photoreactive derivative of influenza virus nucleoprotein peptide NP(336-355Y) and immunoprecipitations with antibodies to class I MHC molecules, that peptide was found to bind to immunopurified class I MHC molecules from HLA-B37+ but not HLA-B37- cells. Binding of the [125I]NP peptide increased from 6 to 12 hr of incubation and was competed by unlabeled, NP peptide but not by HLA-A2-restricted, influenza virus matrix MA(57-73). The principal microsomal membrane proteins binding [125I]NP were about 65, 45 and 33 kD.
Mol Immunol
PMID:Binding of radioiodinated influenza virus peptides to class I MHC molecules and to other cellular proteins as analyzed by gel filtration and photoaffinity labeling. 206 16

Local homology was found between a conservative region of the family of alpha-subunits of GTP-binding proteins and the ganglioside-binding site of influenza virus hemagglutinins. Both families of proteins have similar patterns of distribution of hydrophilic and hydrophobic amino acid residues. GTP-binding proteins and hemagglutinins are proposed to have a common molecular mechanism which underlies their attachment to cell membrane.
Mol Biol (Mosk)
PMID:[G-proteins have a sequence similar to ganglioside-binding hemagglutinins from the influenza virus]. 212 71

The purpose of this study was to examine the effect of treatment with the biologic response modifier Pyrexol on murine host resistance to various infectious organisms. Adult female CD1 mice were treated with a single subcutaneous 100-micrograms injection of Pyrexol at 14, 7, 5, 2, or 1 day prior to infection with various infectious organisms. These organisms included the Herpes simplex type 2 and influenza viruses, as well as the bacteria Listeria monocytogenes and Streptococcus zooepidemicus. Pyrexol treatment was found to significantly potentiate resistance to Listeria organisms, but had no appreciable effect on resistance to any of the other organisms tested. Previous reports have demonstrated that treatment with Pyrexol augments a number of cell-mediated immune parameters, several of which have been shown to be responsible for the elimination of Listeria organisms. These results suggest that Pyrexol is capable of selectively potentiating host resistance to infection.
Mol Biother 1990 Sep
PMID:Selective potentiation of host resistance in mice following treatment with Pyrexol. 217 62

Phylogenetic trees for the human T-cell leukemia virus type I (HTLV-I) and its related viruses were constructed by use of nucleotide sequences of the long terminal repeat (LTR) and the tax gene. The trees showed that the viruses diverged from a common ancestral virus and that they are classified into two groups whose hosts are either primates or bovines. However, the topology of the trees for the viruses differed from that for the hosts. This suggests that HTLV-I and HTLV-I-related viruses evolved independently of host-species divergence and that interspecies transmission between human and monkeys occurred in the past. The nucleotide diversity of the tax genes of HTLV-I was estimated to be 0.025. This value is more than 10 times larger than that of human globin genes, but it is about 20 times smaller than that of hemagglutinin genes of influenza A viruses. Thus, the genetic variability of the HTLV-I genes seems to be higher than that of nuclear genes but much lower than the genes of typical RNA viruses. Furthermore, we examined functional constraints on the overlapping region of the rex and tax genes. The results obtained imply that for the overlapping region, the tax gene has much stronger constraints against amino acid changes than the rex gene.
J Mol Evol 1990 Dec
PMID:Molecular evolution of human T-cell leukemia virus. 217 98

Repeated intranasal infection of Balb/c mice with A/PR/8 influenza virus induced an intense antiviral IgG response dominated by the IgG2a subclass, and accompanied by the appearance of IgG2a reactive autoantibodies. Cells producing IgG2a reactive autoantibodies could then be cloned as hybridomas from the virus infected animals. Monoclonal antibodies produced by selected hybridomas U28, Z26 and Z41 produced IgM-type antibodies with strong specificity for the IgG2a isotype bearing "a" allotypic determinants on the Fc region. These IgG2a specific autoantibodies showed highly preferred binding to solid phase bound or aggregated IgG2a, compared to soluble native IgG2a. Based on these characteristics they were classified as mono-reactive rheumatoid factor (RF)-like autoantibodies. Passive administration of IgM type IgG2a-specific autoantibodies to influenza virus infected animals resulted in a long-term reduction in the secondary antiviral response. This could be demonstrated by decreased virus neutralizing activity of the serum and diminished level of IgG2a-type anti-viral antibodies. A similar effect was observed in Balb/c mice contact sensitized with oxazolone: passive administration of RF-like antibodies resulted in reduced IgG2a response to oxazolone while the level of antibodies belonging to other isotypes was not influenced. These results suggest an isotype-specific regulatory function of these RF-like autoantibodies presumably acting via antigen-antibody complexes.
Mol Immunol 1990 Dec
PMID:In vivo manipulation of IgG2a production by isotype-specific autoantibodies. 217 47

Enveloped animal viruses enter their host cells by a process of membrane fusion. This fusion can occur at the cell plasma membrane or within the endocytic vacuolar system, depending on the characteristics of the virus fusion protein. Examples of both pathways of viral entry are detailed in this review. Semliki Forest virus (SFV) is presented as a well-studied prototype of those viruses which use endocytic uptake in order to infect cells. Fusion of endocytosed SFV is specifically triggered by the acidic pH present within the endocytic pathway, which causes specific conformational changes in the SFV spike protein. While the overall features of endocytic uptake are similar for all viruses which use this pathway, the mechanism by which the viruses then cause fusion appears to differ significantly between them. The best understood fusion mechanism is that of influenza virus, for which sequences involved in pH-dependent fusion can be correlated with the crystallographic structure of the spike protein. In contrast to these pH-dependent virus systems, the entry of human immunodeficiency virus (HIV) into cells occurs by a pH-independent fusion mechanism probably involving fusion at the plasma membrane. The data to date on HIV fusion, endocytosis and entry are summarized as an example of this pathway.
Mol Biol Med 1990 Feb
PMID:Mechanisms of enveloped virus entry into cells. 218 68

Published data and authors' original material on the use of temperaturesensitive influenza virus mutants (ts) as donors in attenuation process aimed at obtaining the recombinant live influenza vaccines (LIV) are reviewed. The so called cold adapted ts donors are shown to be superior for this aim. The data are presented in the review on the association of the mutations in the genome of cold adapted donors with attenuation, on the reactivity, immunogenicity and genetical stability of the recombinant LIVs constructed on the basis of the cold adapted donors.
Mol Gen Mikrobiol Virusol 1990 Mar
PMID:[Genetic basis for construction of the life influenza type A vaccine using temperature-sensitive mutants]. 219 19

The published data on the lipids composition of influenza virus, the significance of lipid-protein interactions for support of the virion structure are reviewed. The roles of viral and cellular membrane lipids in the different stages of viral interaction with the host cell: viral adsorption to the cellular surface, penetration into the cell, maturation and assembly of virions are discussed. The data on the significance of lipid composition phenotype of the virus and host cell in realization of the viral infection of the cell are reviewed.
Mol Gen Mikrobiol Virusol 1990 Apr
PMID:[The role of lipids in the interaction of influenza virus with the host cell]. 219 22

Polymerase basic protein 1 (PB1) of influenza virus (A/WSN/33), when expressed from cloned cDNA in the absence of other viral proteins, accumulates in the nucleus. We have examined the location and nature of the nuclear localization signal of PB1 by using deletion mutants and chimeric constructions with chicken muscle pyruvate kinase, a cytoplasmic protein. Our studies showed some novel features of the nuclear localization signal of PB1. The signal was present internally within residues 180 to 252 of PB1. Moreover, unlike most nuclear localization signals, it was not a single stretch of contiguous amino acids. Instead, it possessed two discontinuous regions separated by an intervening sequence which could be deleted without affecting its nuclear localization property. On the other hand, deletion of either of the two signal regions rendered the protein cytoplasmic, indicating that the function of both regions is required for nuclear localization and that one region alone is not sufficient. Both of these signal regions contained short stretches of basic residues. Possible ways by which this novel bipartite signal can function in nuclear localization are discussed.
Mol Cell Biol 1990 Aug
PMID:Function of two discrete regions is required for nuclear localization of polymerase basic protein 1 of A/WSN/33 influenza virus (H1 N1). 219 48


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