SARS-CoV envelope protein palmitoylation or nucleocapid association is not required for promoting virus-like particle production.
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.
Ying-Tzu
YT
Tseng
Shiu-Mei
SM
Wang
Kuo-Jung
KJ
Huang
Department of Medical Research, Taipei Veterans General Hospital, 201, Sec, 2, Shih-Pai Road, Taipei 11217, Taiwan. chintien@ym.edu.tw.
Chin-Tien
CT
Wang
D006801:Humans; D054878:Lipoylation; D019251:Nucleocapsid / Q000235:genetics / Q000378:metabolism*; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000235:genetics* / Q000254:growth & development; D019065:Virus Assembly / Q000235:genetics
D014759:Viral Envelope Proteins