The structural basis for an essential subunit interaction in influenza virus RNA polymerase

Obayashi, E.; Yoshida, Hisashi; Kawai, Fumihiro; Shibayama, Naoya; Kawaguchi, Akiko; Nagata, Kyosuke; Tame, J.R.H.; Park, Sam-Yong

doi:10.1038/nature07225

Cited by 230 publications

(293 citation statements)

References 39 publications

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“…ml 21 and HAU ml 21 were determined for viral particles in the collected allantoic fluids at 36 h p.i. He et al, 2008;Obayashi et al, 2008). This assumption was supported by our finding that PB1 Gi can enhance the polymerase activity (especially the transcription activity) of 7+1 PR8 reassortant virus when compared with PR8 wt (Fig.…”

Section: Discussionsupporting

confidence: 77%

The PB1 segment of an influenza A virus H1N1 2009pdm isolate enhances the replication efficiency of specific influenza vaccine strains in cell culture and embryonated eggs

Mostafa

Kanrai

Ziebuhr

et al. 2016

Journal of General Virology

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Influenza vaccine strains (IVSs) contain the haemagglutinin (HA) and neuraminidase (NA) genome segments of relevant circulating strains in the genetic background of influenza A/ PR/8/1934 virus (PR8). Previous work has shown that the nature of the PB1 segment may be a limiting factor for the efficient production of IVSs. Here, we showed that the PB1 segment (PB1 Gi ) from the 2009 pandemic influenza A virus (IAV) A/Giessen/06/2009 (Gi wt, H1N1pdm) may help to resolve (some of) these limitations. We produced a set of recombinant PR8-derived viruses that contained (i) the HA and NA segments from representative IAV strains (H3N2, H5N1, H7N9, H9N2); (ii) the PB1 segment from PR8 or Gi wt, respectively; and (iii) the remaining five genome segments from PR8. Viruses containing the PB1 Gi segment, together with the heterologous HA/NA segments and five PR8 segments (5+2+1), replicated to higher titres compared with their 6+2 counterparts containing six PR8 segments and the equivalent heterologous HA/NA segments. Compared with PB1 PR8 -containing IVSs, viruses with the PB1 Gi segment replicated to higher or similar titres in both cell culture and embryonated eggs, most profoundly IVSs of the H5N1 and H7N9 subtype, which are known to grow poorly in these systems. IVSs containing either the PB1 Gi or the cognate PB1 segment of the respective specific HA/NA donor strain showed enhanced or similar virus replication levels. This study suggests that substitution of PB1 PR8 with the PB1 Gi segment may greatly improve the large-scale production of PR8-derived IVSs, especially of those known to replicate poorly in vitro. INTRODUCTIONInfluenza viruses belong to the family Orthomyxoviridae and are classified into three genera termed Influenza virus A, B and C. Among these, influenza A viruses (IAVs) pose the greatest threat to human and animal health. They contain eight segments of negative-sense ssRNA (Ritchey et al., 1976;Shaw & Palese, 2013). The eight genomic segments encode at least 10 viral proteins, comprising the three subunits of the viral RNA polymerase complex [polymerase basic protein 2 (PB2), polymerase basic protein 1 (PB1) and polymerase acidic protein (PA)], the surface glycoproteins [haemagglutinin (HA) and neuraminidase (NA)], the nucleoprotein (NP), the matrix protein (M1), the ion channel protein (M2), the non-structural protein 1 (NS1) and the nuclear export protein (NEP). IAVs are genetically diverse, with new strains rapidly emerging by point mutations introduced by the low-fidelity viral RNA replicase (potentially resulting in antigenic drift if changes occur in the HA and/or NA coding sequences and affect important antigenic epitopes) or by genetic reassortment of genomic segments (potentially leading to antigenic shift if antigenically distant HA and NA segments are incorporated). Minor and major antigenic changes in the HA and NA proteins of circulating IAV are important driving forces for the emergence of new strains causing epidemics or even major pandemics (Neumann et al., 2009;Peng et al., 2014;Smith...

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Section: Discussionsupporting

confidence: 77%

The PB1 segment of an influenza A virus H1N1 2009pdm isolate enhances the replication efficiency of specific influenza vaccine strains in cell culture and embryonated eggs

Mostafa

Kanrai

Ziebuhr

et al. 2016

Journal of General Virology

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“…A variety of differences exist between PA proteins from S009, WSN, 1918, or NY312, including amino acids 55, 100, 382, and 552 which have been identified as key residues that distinguish avian and human polymerases (40). The consequences of these differences are not obvious, as they do not occur in residues important for endonuclease activity or binding to PB1 (41)(42)(43)(44). Further investigation is required to determine the residues in PA that contribute to increased polymerase activity.…”

Section: Discussionmentioning

confidence: 99%

Adaptive strategies of the influenza virus polymerase for replication in humans

Mehle¹,

Doudna

2009

Proc. Natl. Acad. Sci. U.S.A.

335

373

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Transmission of influenza viruses into the human population requires surmounting barriers to cross-species infection. Changes in the influenza polymerase overcome one such barrier. Viruses isolated from birds generally contain polymerases with the aviansignature glutamic acid at amino acid 627 in the PB2 subunit. These polymerases display restricted activity in human cells. An adaptive change in this residue from glutamic acid to the human-signature lysine confers high levels of polymerase activity in human cells. This mutation permits escape from a species-specific restriction factor that targets polymerases from avian viruses. A 2009 swineorigin H1N1 influenza A virus recently established a pandemic infection in humans, even though the virus encodes a PB2 with the restrictive glutamic acid at amino acid 627. We show here that the 2009 H1N1 virus has acquired second-site suppressor mutations in its PB2 polymerase subunit that convey enhanced polymerase activity in human cells. Introduction of this polymorphism into the PB2 subunit of a primary avian isolate also increased polymerase activity and viral replication in human and porcine cells. An alternate adaptive strategy has also been identified, whereby introduction of a human PA subunit into an avian polymerase overcomes restriction in human cells. These data reveal a strategy used by the 2009 H1N1 influenza A virus and identify other pathways by which avian and swine-origin viruses may evolve to enhance replication, and potentially pathogenesis, in humans.2009 A(H1N1) ͉ PB2 ͉ species barriers

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“…2). Some of these interactions have been verified by co-crystallisation [55][56][57] and functional studies. 58 Also, some additional PB2-PA and PB1-PB2 interactions have been described in reference 40 and 59, that may play structural and/or regulatory roles in the activity of the viral polymerase.…”

Section: The Polymerase Complexmentioning

confidence: 99%

“…2). In addition to the subunit interfaces mentioned above, the atomic structures of domains of the PA and PB2 subunits have been determined 47,55,56,[63][64][65][66][67] but no information on the structure of the polymerase active site in the PB1 subunit is yet available. The data reported allowed the identification of the polymerase cap-binding site in PB2 and established that the endonuclease responsible for cap-snatching resides at the N-terminal region of PA, in agreement with previous genetic contacts detected in the cryo-EM structure of the mini-RNP.…”

confidence: 99%