Multifunctional protein which associates with itself through both covalent and non-covalent interactions to provide the basis for viral assembly. May play a role in the regulation of cellular gene expression during infection by interacting with host HIC. Plays a role in the inhibition of the dsRNA-mediated IFN induction pathway by inhibiting host IRF3 phosphorylation and nuclear translocation. Homooligomer. Interacts with host PABPC1 (via C-terminus). Interacts with host HIC; this interaction may regulate the expression of different cellular genes. Belongs to the arteriviridae nucleocapsid family.