The multifunctional nucleocapsid (N) protein in SARS-CoV-2 binds the ~30 kb viral RNA genome to aid its packaging into the 80–90 nm membrane-enveloped virion. The N protein is composed of N-terminal RNA-binding and C-terminal dimerization domains that are flanked by three intrinsically disordered regions. Here we demonstrate that the N protein’s central disordered domain drives phase separation with RNA, and that phosphorylation of an adjacent serine/arginine rich region modulates the physical properties of the resulting condensates. In cells, N forms condensates that recruit the stress granule protein G3BP1, highlighting a potential role for N in G3BP1 sequestration and stress granule inhibition. The SARS-CoV-2 membrane (M) protein independently induces N protein phase separation, and three-component mixtures of N + M + RNA form condensates with mutually exclusive compartments containing N + M or N + RNA, including annular structures in which the M protein coats the outside of an N + RNA condensate. These findings support a model in which phase separation of the SARS-CoV-2 N protein contributes both to suppression of the G3BP1-dependent host immune response and to packaging genomic RNA during virion assembly. The SARS-CoV-2 nucleocapsid (N) protein binds the viral RNA genome and contains two ordered domains flanked by three intrinsically-disordered regions. Here, the authors show that RNA binding induces liquid-liquid phase separation of N, which is driven by its central intrinsically-disordered region and is modulated by phosphorylation. The SARS-CoV-2 Membrane (M) protein also phase-separates with N, and three-component mixtures of N + M + RNA form mutually exclusive compartments containing N + M or N + RNA.
【저자키워드】 SARS-CoV-2, RNA, 【초록키워드】 Structure, Stress, arginine, M protein, Protein, Viral, Host immune response, cells, nucleocapsid, N protein, Phosphorylation, membrane, SARS-CoV-2 N protein, binding, G3BP1, genomic RNA, physical properties, Support, Serine, suppression, domain, separation, viral RNA genome, virion assembly, virion, SARS-CoV-2 nucleocapsid, N-terminal, sequestration, regions, physical, bind, resulting, composed, form, contribute, modulate, induce, driven by, multifunctional, C-terminal, highlighting, intrinsically, modulated, recruit, the SARS-CoV-2, 【제목키워드】 SARS-CoV-2 nucleocapsid, form,