Introduction: It has also been found that the human A/Hong Kong/156/1997 (H5N1) influenza virus NS1 F103L and M106I mutations could both increase IFN antagonism and virulence via increasing cytoplasmic NS1 expression as well as increased binding with host factors such as RIG-I.
Identification of Amino Acid Residues Responsible for Inhibition of Host Gene Expression by Influenza A H9N2 NS1 Targeting of CPSF30.
Result: To test the individual and combined contribution of these amino acid residues in the inhibition of host protein synthesis, we introduced the amino acid changes D92E, F103L, M106I, A112T, S114P, D125G, and D
Result: We identified seven amino acids changes between WI/66 and HK/97 (D92E, F103L, M106I, A112T, S114P, D125G, and D139N) that could be involved in the presence/lack of inhibition of host gene expression between the different H9N2 NS1 proteins (Figure 4, red).
Residues F103 and M106 within the influenza A virus NS1 CPSF4-binding region regulate interferon-stimulated gene translation initiation.
Abstract: Recombinant (r) IAVs encoding F103L and M106I mutations in NS1 replicate to significantly lower viral titers in human A549 lung epithelial cells and primary type II alveolar cells.
G45R mutation in the nonstructural protein 1 of A/Puerto Rico/8/1934 (H1N1) enhances viral replication independent of dsRNA-binding activity and type I interferon biology.
Discussion: An adaptation of amino acids on NS1, F103L and M106I, of human influenza A/Hong Kong/1/68(H3N2) has been reported to be associated with the increased virus replication and virulence in mice and human thereby the occurrence of G45R mutation on NS1 of pandemic human 2009 H1N1 virus might be one of crucial factors to cause severe disease.
Influenza A/Hong Kong/156/1997(H5N1) virus NS1 gene mutations F103L and M106I both increase IFN antagonism, virulence and cytoplasmic localization but differ in binding to RIG-I and CPSF30.
Abstract: Human H1N1 and H3N2 NS1 proteins bound to the CARD, helicase and RD RIG-I domains, whereas the H5N1 NS1 with the same consensus 103F and 106M mutations did not bind these domains, which was totally or partially restored by the M106I or F103L mutations respectively.
Abstract: RESULTS: Each of the F103L and M106I mutations contributes additively to virulence to reduce the lethal dose by >800 and >3,200 fold respectively by mediating alveolar tissue infection with >100 fold increased infectious yields.
Abstract: The human A/HK/156/1997 (H5N1) virus that transmitted from poultry possesses NS1 gene mutations F103L + M106I that are virulence determinants in the
Identification of adaptive mutations in the influenza A virus non-structural 1 gene that increase cytoplasmic localization and differentially regulate host gene expression.
Abstract: While host genes were predominantly down regulated for the HGR group of mutants (D2N, V23A, F103L, M106I+L98S, L98S, M106V, and M106V+M124I), the LGR phenotype mutants (D125G, M106I, V180A, V226I, and R227K) were characterized by a predominant up regulation of host genes.
Adaptive mutation in influenza A virus non-structural gene is linked to host switching and induces a novel protein by alternative splicing.
Introduction: For instance, 226I and 227K NS1 mutations are convergent with the 1918 H1N1 Spanish flu, and the F103L and M106I NS1 mutations, that have been shown to be adaptive, have been previously selected in the highly pathogenic avian H5N1 and its precursor from low pathogenic H9N2 lineages.
Influenza A virus NS1 gene mutations F103L and M106I increase replication and virulence.
Result: The rPR8-HK-NS-wt recombinant also induced low levels of IFN-beta (22 pg/ml) whereas each of the recombinants rPR8-HK-NS-F103L or rPR8-HK-NS-M106I induced 2 and 3 fold more IFN-beta respectively compared to rPR8-HK-NS-wt (40 and 68 pg/ml respectively) while the double mutations together had a cumulative effect on incre
Result: The rate of viral protein synthesis was enhanced by the F103L mutation at all time points as demonstrated for the M1 and NS1 bands with the most dramatic increase shown early after infection (at 2 hpi).
Discussion: F103L and M106I Mutations enhance protein synthesis.
IV mutation literature information.
PMID: 
2018
Veterinary research
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