SARS-CoV-2 Omicron variant nucleocapsid protein (N protein)

The SARS-CoV-2 Omicron variant nucleocapsid (N) protein is a highly abundant structural protein that plays a pivotal role in the viral life cycle by packaging the positive-sense RNA genome into a protective ribonucleoprotein (RNP) complex (UniProt: P0DTC9). It is essential for viral replication, transcription, and assembly through its interactions with the viral membrane (M) protein and genomic RNA (PMID: 32800201). In the Omicron variant, the N protein harbors specific mutations, including P13L, a three-amino acid deletion (31-33), and the R203K/G204R substitution, which are thought to enhance viral fitness and contribute to the variant's increased transmissibility (PMID: 35241416). Beyond its structural functions, the N protein acts as an immune modulator by suppressing host interferon signaling and helping the virus evade innate immunity (PMID: 33500253). While the Spike protein is the primary target for current vaccines, the N protein is the chief target for rapid diagnostic antigen tests because it is expressed at high levels and is relatively more conserved across variants (CDC, 2024). Therapeutically, the N protein is an emerging target for antivirals, including small molecules that disrupt its dimerization or its interaction with host kinases like Casein Kinase II (PMID: 32511302, PMID: 34509436).

Other names

NucleoproteinNucleocapsid proteinSARS-CoV-2 N proteinSARS-CoV-2 Omicron NProtein N

Interference with the phosphorylation of the N protein by host kinases or direct inhibition of N protein-RNA binding and dimerization to prevent viral replication and assembly.