Co-expression of the capsid proteins of Cowpea mosaic virus in insect cells leads to the formation of virus-like particles.
The regions of RNA-2 of Cowpea mosaic virus (CPMV) that encode the Large (L) and Small (S) coat proteins were expressed either individually or together in Spodoptera frugiperda (sf21) cells using baculovirus vectors. Co-expression of the two coat proteins from separate promoters in the same construct resulted in the formation of virus-like particles whose morphology closely resembled that of native CPMV virions. No such particles were formed when the individual L and S proteins were expressed. Sucrose gradient centrifugation of the virus-like particles showed that they had the sedimentation characteristics of empty (protein-only) shells. The results confirm that the 60 kDa L-S fusion is not an obligate intermediate in the virion assembly pathway and indicate that expression of the coat proteins in insect cells will provide a fruitful route for the study of CPMV morphogenesis.
Shanks
Michael
M
Department of Virus Research, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK1.
Lomonossoff
George P
GP
Department of Virus Research, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK1.
D000818:Animals; D015153:Blotting, Western; D002213:Capsid / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002460:Cell Line; D017798:Comovirus / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D015870:Gene Expression; D016253:Microscopy, Immunoelectron; D011401:Promoter Regions, Genetic / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera; D014162:Transfection; D019065:Virus Assembly
D012367:RNA, Viral