CoV and RNAi

(pmid: 26085159) nucleocapsid protein (N protein) of coronaviruses suppresses RNAi triggered by either short hairpin RNAs or small interfering RNAs in mammalian cells. Mouse hepatitis virus (MHV) is closely related to SARS-CoV in the family Coronaviridae and was used as a coronavirus replication model. The replication of MHV increased when the N proteins were expressed in trans, while knockdown of Dicer1 or Ago2 transcripts facilitated the MHV replication in mammalian cells. These results support the hypothesis that RNAi is a part of the antiviral immunity responses in mammalian cells.

N as supressor of RNA silencing. N protein could function as a VSR (viral suppressors of RNA silencing) through its double-stranded RNA binding activity.

see pmid: 17375004

evidence exists that viruses can differentially affect siRNA versus miRNA biogenesis22 and both cellular and viral encoded miRNAs may affect viral replication.23,24