Background Coronavirus membrane (M) proteins are capable of interacting with nucleocapsid (N) and envelope (E) proteins. Severe acute respiratory syndrome coronavirus (SARS-CoV) M co-expression with either N or E is sufficient for producing virus-like particles (VLPs), although at a lower level compared to M, N and E co-expression. Whether E can release from cells or E/N interaction exists so as to contribute to enhanced VLP production is unknown. It also remains to be determined whether E palmitoylation or disulfide bond formation plays a role in SARS-CoV virus assembly. Results SARS-CoV N is released from cells through an association with E protein-containing vesicles. Further analysis suggests that domains involved in E/N interaction are largely located in both carboxyl-terminal regions. Changing all three E cysteine residues to alanines did not exert negative effects on E release, E association with N, or E enhancement of VLP production, suggesting that E palmitoylation modification or disulfide bond formation is not required for SARS-CoV virus assembly. We found that removal of the last E carboxyl-terminal residue markedly affected E release, N association, and VLP incorporation, but did not significantly compromise the contribution of E to efficient VLP production. Conclusions The independence of the SARS-CoV E enhancement effect on VLP production from its viral packaging capacity suggests a distinct SARS-CoV E role in virus assembly.
【초록키워드】 coronavirus, SARS-CoV, Proteins, virus, Protein, nucleocapsid, membrane, VLP, association, Interaction, Analysis, disulfide bond, acute respiratory syndrome, Virus-like particle, residue, domain, Alanine, Modification, SARS-CoV virus, vesicles, VLPs, Effect, regions, co-expression, Cell, Result, affected, significantly, involved, required, contribute, producing, Changing, SARS-CoV N, released, SARS-CoV E, cysteine residue, N or E, 【제목키워드】 SARS-CoV, envelope protein, association, required,