The Host Factor ANP32A Is Required for Influenza A Virus vRNA and cRNA Synthesis.

TitleThe Host Factor ANP32A Is Required for Influenza A Virus vRNA and cRNA Synthesis.
Publication TypeJournal Article
Year of Publication2022
AuthorsNilsson-Payant, BE, tenOever, BR, Velthuis, AJWTe
JournalJ Virol
Volume96
Issue4
Paginatione0209221
Date Published2022 02 23
ISSN1098-5514
KeywordsAnimals, Chickens, Genome, Viral, Humans, Influenza A virus, Mutation, Nuclear Proteins, Protein Domains, Ribonucleoproteins, RNA, Viral, RNA-Binding Proteins, RNA-Dependent RNA Polymerase, Viral Proteins, Viral Replicase Complex Proteins, Virus Replication
Abstract

<p>Influenza A viruses are negative-sense RNA viruses that rely on their own viral replication machinery to replicate and transcribe their segmented single-stranded RNA genome. The viral ribonucleoprotein complexes in which viral RNA is replicated consist of a nucleoprotein scaffold around which the RNA genome is wound, and a heterotrimeric RNA-dependent RNA polymerase that catalyzes viral replication. The RNA polymerase copies the viral RNA (vRNA) via a replicative intermediate, called the cRNA, and subsequently uses this cRNA to make more vRNA copies. To ensure that new cRNA and vRNA molecules are associated with ribonucleoproteins in which they can be amplified, the active RNA polymerase recruits a second polymerase to encapsidate the cRNA or vRNA. Host factor ANP32A has been shown to be essential for viral replication and to facilitate the formation of a dimer between viral RNA polymerases. Differences between mammalian and avian ANP32A proteins are sufficient to restrict viral replication. It has been proposed that ANP32A is only required for the synthesis of vRNA molecules from cRNA but not vice versa. However, this view does not match recent molecular evidence. Here we use minigenome assays, virus infections, and viral promoter mutations to demonstrate that ANP32A is essential for both vRNA and cRNA synthesis. Moreover, we show that ANP32A is not only needed for the actively replicating polymerase, but not for the polymerase that is encapsidating nascent viral RNA products. Overall, these results provide new insights into influenza A virus replication and host adaptation. Zoonotic avian influenza A viruses pose a constant threat to global health, and they have the potential to cause pandemics. Species variations in host factor ANP32A play a key role in supporting the activity of avian influenza A virus RNA polymerases in mammalian hosts. Here we show that ANP32A acts at two stages in the influenza A virus replication cycle, supporting recent structural experiments, in line with its essential role. Understanding how ANP32A supports viral RNA polymerase activity and how it supports avian polymerase function in mammalian hosts is important for understanding influenza A virus replication and the development of antiviral strategies against influenza A viruses.</p>

DOI10.1128/jvi.02092-21
Alternate JournalJ Virol
PubMed ID34935435
PubMed Central IDPMC8865535
Grant List5R01AI14588 / / HHS | National Institutes of Health (NIH) /
R01 AI123155 / AI / NIAID NIH HHS / United States
R21 AI147172 / AI / NIAID NIH HHS / United States
R21AI147172 / / HHS | National Institutes of Health (NIH) /
R01 AI145882 / AI / NIAID NIH HHS / United States
/ WT_ / Wellcome Trust / United Kingdom
206579/Z/17/Z / WT_ / Wellcome Trust / United Kingdom
102053/Z/13/Z / WT_ / Wellcome Trust / United Kingdom