tetano
Editor, Senior Moderator
J Virol. 2016 Apr 20. pii: JVI.00494-16. [Epub ahead of print]
[h=1]RNA-free and ribonucleoprotein-associated influenza virus polymerases directly bind the serine-5 phosphorylated carboxyl-terminal domain of host RNA polymerase II.[/h] Mart?nez-Alonso M[SUP]1[/SUP], Hengrung N[SUP]2[/SUP], Fodor E[SUP]3[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Influenza viruses subvert the transcriptional machinery of their hosts to synthesise their own viral mRNA. Ongoing transcription by cellular RNA polymerase II (Pol II) is required for viral mRNA synthesis. By a process known as cap-snatching, the virus steals short 5' capped RNA fragments from host capped RNAs and uses these to prime viral transcription. An interaction between the influenza A virus RNA polymerase and the C-terminal domain (CTD) of the large subunit of Pol II has been established, but the molecular details of this interaction remain unknown. We show here that influenza virus ribonucleoprotein (vRNP) complex binds to the CTD of transcriptionally engaged Pol II. Furthermore, we provide evidence that the viral polymerase binds directly to the serine-5 phosphorylated form of the Pol II CTD, both in the presence and absence of viral RNA, and show that this interaction is conserved in evolutionarily distant influenza viruses. We propose a model in which direct binding of the viral RNA polymerase in the context of vRNPs to Pol II early in infection facilitates cap-snatching, while we suggest that binding of free viral polymerase to Pol II late in infection may trigger Pol II degradation.
[h=4]IMPORTANCE:[/h] Influenza viruses cause yearly epidemics and occasional pandemics that pose a threat to human health as well as represent a large economic burden to healthcare systems globally. Existing vaccines are not always effective as they may not exactly match the circulating viruses. Furthermore, there are a limited number of antivirals available, and development of resistance to these is a concern. New measures to combat influenza are needed, but before they can be developed it is necessary to better understand the molecular interactions between influenza viruses and their host cells. By providing further insights into the molecular details of how influenza viruses hijack the host transcriptional machinery, we aim to uncover novel targets for development of antivirals.
Copyright ? 2016 Mart?nez-Alonso et al.
PMID: 27099314 [PubMed - as supplied by publisher] Free full text
[h=1]RNA-free and ribonucleoprotein-associated influenza virus polymerases directly bind the serine-5 phosphorylated carboxyl-terminal domain of host RNA polymerase II.[/h] Mart?nez-Alonso M[SUP]1[/SUP], Hengrung N[SUP]2[/SUP], Fodor E[SUP]3[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Influenza viruses subvert the transcriptional machinery of their hosts to synthesise their own viral mRNA. Ongoing transcription by cellular RNA polymerase II (Pol II) is required for viral mRNA synthesis. By a process known as cap-snatching, the virus steals short 5' capped RNA fragments from host capped RNAs and uses these to prime viral transcription. An interaction between the influenza A virus RNA polymerase and the C-terminal domain (CTD) of the large subunit of Pol II has been established, but the molecular details of this interaction remain unknown. We show here that influenza virus ribonucleoprotein (vRNP) complex binds to the CTD of transcriptionally engaged Pol II. Furthermore, we provide evidence that the viral polymerase binds directly to the serine-5 phosphorylated form of the Pol II CTD, both in the presence and absence of viral RNA, and show that this interaction is conserved in evolutionarily distant influenza viruses. We propose a model in which direct binding of the viral RNA polymerase in the context of vRNPs to Pol II early in infection facilitates cap-snatching, while we suggest that binding of free viral polymerase to Pol II late in infection may trigger Pol II degradation.
[h=4]IMPORTANCE:[/h] Influenza viruses cause yearly epidemics and occasional pandemics that pose a threat to human health as well as represent a large economic burden to healthcare systems globally. Existing vaccines are not always effective as they may not exactly match the circulating viruses. Furthermore, there are a limited number of antivirals available, and development of resistance to these is a concern. New measures to combat influenza are needed, but before they can be developed it is necessary to better understand the molecular interactions between influenza viruses and their host cells. By providing further insights into the molecular details of how influenza viruses hijack the host transcriptional machinery, we aim to uncover novel targets for development of antivirals.
Copyright ? 2016 Mart?nez-Alonso et al.
PMID: 27099314 [PubMed - as supplied by publisher] Free full text