PVA infection and host RNA metabolism

Virus infection begins by the production of viral replication proteins and establishment of the replication complex for multiplication of progeny genomes. Newly synthesized vRNAs released from the replication complexes fight against the host’s defense pathways. Therefore, for a robust and productive infection, the viral RNA molecules need to be able to suppress gene silencing and cope also with the other cellular RNA metabolic pathways and degradation machineries (reviewed in [1]).

Multifunctional potyviral protein called helper component-proteinase (HCPro) is a suppressor of RNA silencing. We found that it induces RNA granules (PGs), which are required to overcome active RNA silencing, achieve optimal viral gene expression and support virus accumulation [2]. We proposed that PGs are the sites for active RNA silencing suppression. Many of the PG-associated host factors are important susceptibility factors of PVA infection.

  1. Mäkinen, K., Lõhmus A., and Pollari, M. 2017. Plant RNA Regulatory Network and RNA Granules in Virus Infection. Solicited review. Front Plant Sci. 8:2093. doi:10.3389/fpls.2017.02093. eCollection 2017.
  2. Hafren, A., Lõhmus, A, and Mäkinen, K. (2015) “Formation of Potato virus A-induced RNA granules and viral translation are interrelated processes required for optimal virus accumulation” PLOS Pathogens, 11(12):e1005314. doi: 10.1371/journal.ppat.1005314.