Introduction: The majority of the mammalian adaptive substitutions occur in the PB2 protein; E627K and D710N are two well-characterized substitutions in PB2 protein, which are critical for mammalian adaptation in multiple subtypes of avian influenza viruses.
Prevailing I292V PB2 mutation in avian influenza H9N2 virus increases viral polymerase function and attenuates IFN-beta induction in human cells.
PMID: 31305236
2019
The Journal of general virology
Introduction: To overcome this restriction, the avian PB2 gene needs to acquire certain mutational changes to improve its activity in mammalian cells, as exemplified in PB2-E627K, -D701N, -T271A, -K526R and -A588V.
Discussion: PB2-E627K mutation alters polymerase activity by affecting the interaction of PB2 with NP and exhib
Discussion: Increased polymerase activity conferred by other mutations on PB2, such as PB2-E627K, has been shown to be crucial for AIVs to adapt to mammalian hosts.
Continuing evolution of H6N2 influenza a virus in South African chickens and the implications for diagnosis and control.
Result: In the PB2 protein, K73R, A199S, L475 M, D567N, E627K, A661T and K702R mutations are associated with IAVs capacity to infect humans.
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.
V292I mutation in PB2 polymerase induces increased effects of E627K on influenza H7N9 virus replication in cells.
Abstract: However, HA A150V and PA A343T seemed to attenuate PB2 E627K in vivo, which implies the difference between mixed viral populations under natural condition and single population under experiment, specialization and cooperation in quasispecies is important in the process of adaption.
Abstract: In addition, we show that PA A343T dramatically exacerbates the effect of PB2 E627K on viral polymerase activity; when combined, these two substitutions work synergistically.
Abstract: The well-known PB2 E627K substitution increased
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.
New Threats from H7N9 Influenza Virus: Spread and Evolution of High- and Low-Pathogenicity Variants with High Genomic Diversity in Wave Five.
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.
Challenge for One Health: Co-Circulation of Zoonotic H5N1 and H9N2 Avian Influenza Viruses in Egypt.
Abstract: The H5N1 viruses acquired enhanced bird-to-human transmissibility by (1) altering amino acids in hemagglutinin (HA) that enable binding affinity to human-type receptors, (2) loss of the glycosylation site and 130 loop in the HA protein and (3) mutation of E627K in the PB2 protein to enhance viral replication in mammalian hosts.
Introduction: Most Egyptian H5N1 viruses possess two other mutations that may facilitate their transmissibility and replication in mammals: (1) the deletion in the 130 loop (129Delta) with a concurrent loss of glycosylation mutation (T156A) in the HA and (2) E627K mutation in the PB2 protein.
Multiple adaptive amino acid substitutions increase the virulence of a wild waterfowl-origin reassortant H5N8 avian influenza virus in mice.
Abstract: Notably, human-origin viruses were more pathogenic in mice than avian viruses, and the mutations in the PB2 gene associated with adaptation to mammals (E627K, A588V, and D701N) were identified by next-generation sequencing (NGS) and Sanger sequencing of the isolates from infected mice.