Abstract: Importantly, neuraminidase (NA) inhibitor (NAI) resistance (R292K in NA) and mammalian adaptation (e.g., E627K and A588V in PB2) mutations were found in a few non-human-derived HP-H7N9 strains.
Abstract: Notably, the NAI drug-resistant (R292K in NA) and mammalian-adapted (e.g., E627K in PB2) mutations were found in HP-H7N9 not only from human isolates but also from poultry and environmental isolates, indicating increased risks for human infections.
A Single Amino Acid in the Polymerase Acidic Protein Determines the Pathogenicity of Influenza B Viruses.
Introduction: Hence, identifying a common denominator for the enhanced pathogenicity of IBVs, such as the E627K PB2 mutation of avian IAVs, may be of great importance because such defined IBV pathogenic determinants might be useful for the interpretation of IBV virulence and host range.
Introduction: The PB2 E627K mutation of avian IAVs has been suggested to be associated with pathogenicity in mice.
Dynamic Variation and Reversion in the Signature Amino Acids of H7N9 Virus During Human Infection.
PMID: 29688498
2018
The Journal of infectious diseases
Abstract: Neuraminidase (NA)
Abstract: Dual D701N and E627K mutations emerged but failed to achieve predominance in any of the samples.
Introduction: Notably, the oseltamivir-resistant NA R292K mutation increased during antiviral treatment in a fatal case of H7N9 infection, and the PB2 E627K mutation was also identified with increasing frequency during infection in a fatal human case of avian H7N7 influenza virus.
Table: E627K
Figure: The kinetics of R292K and E627K mutations in sequential samples obtained from patients during disease development.
Adaptive Mutations in Influenza A/California/07/2009 Enhance Polymerase Activity and Infectious Virion Production.
Introduction: The E627K (PB2 gene) polymorphism has been reported in in many human isolates with continuing evolution evident at the full-genome level in both human and poultry isolates.
Potential Pandemic of H7N9 Avian Influenza A Virus in Human.
PMID: 30533399
2018
Frontiers in cellular and infection microbiology
Result: E/D627K/N and D701N in PB2 had much higher proportions in human-isolated than avian-isolated H7N9 in all 5 waves (Figure 2).
Result: In comparison, one in three sequences (33.33%) of H9N2 has amino acid change E/D627K/N in wave 4, and one in four sequences (25%) have change D701N in wave 3.
Result: In comparisons of H7N9 and H9N2, the former has high proportions of the amino acid changes V100A in PA and K526R, E/D627K/N, and D701N in PB2.
Discussion: Amino acid changes E/D627K/N
A PB1-K577E Mutation in H9N2 Influenza Virus Increases Polymerase Activity and Pathogenicity in Mice.
Method: Human 293T and chicken DF-1 cells were transfected with pPolI-NP(0)Fluc(0) or pPolGG-NP(0)Fluc(0), together with pRL-null and pCAGGS plasmids expressing wild-type PB2, PB1, PA, and NP, or mutant PB1 K577E or PB2 E627K, by using polyethylenimine (PEI; Polysciences, Inc., Warrington, PA, USA).
Result: Although the virus titers in the lungs of rWT-, rPB1-K577E-, and rPB2-E627K-inoculated mice were similar, those in the nasal turbinates of mutant virus-inoculated mice were significantly higher than that of rWT-inoculat
Tree shrew as a new animal model to study the pathogenesis of avian influenza (H9N2) virus infection.
Discussion: In our experiments, the wild-type H9N2/Y280 virus replicated efficiently in ferrets even without the PB2-E627K mutation, while the difference between the wild type and the PB2 mutant was more significant in tree shrews, supporting the previous finding that tree shrews are susceptible to avian H9N2 virus infection.
Discussion: In our study, both ferrets and tree shrews supported the replication of the H9N2 virus, and this replication was further enhanced by the PB2-E627K mutation.
Discussion: Interestingly, the PB2-E627K mutant clearly replicated more efficiently than the wild-type virus in the ex vivo study, while virus replication was observed only in the lu
Multiple polymerase gene mutations for human adaptation occurring in Asian H5N1 influenza virus clinical isolates.
Discussion: Among these mutations, PB2-E627K and, to lesser extent, PB2-D701N have been described as being critical for avian H5N1 virus replication in mammalian hosts.
Discussion: In fact, the PB2-D701N and PB2-Q591R mutations alone, but not combined with the PB2-E627K mutation, produced a replication advantage for the avian H5N1 virus polymerase during human cell infection.
Discussion: In particular, it should be noted that all Egyptian clade 2.2.1 viruses have the PB2-E627K mutation, whereas all avian viruses in the Asian H5N1 clades, including clade 2.3
Identification of two residues within the NS1 of H7N9 influenza A virus that critically affect the protein stability and function.
Discussion: In addition, either E627K or V598T/I substitution in PB2 contributes to the higher virulence of H7N9 influenza virus than the 2009 pandemic H1N1 influenza virus and the seasonal H3N2 influenza virus through enhancing replication and pathogenicity of H7N9 influenza virus in mammals.
IV mutation literature information.
PMID: 
2018
Journal of virology
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