The replicase/transcriptase polyprotein self-cleaves to form non-structural proteins. Later reading frames encode the four major structural proteins: spike, envelope, membrane, and nucleocapsid.
Protini nyingi za replicase/transcriptase hujikwamilia ili kuunda protini zisizo na muundo. Fremu za baadaye za kusoma husimbua protini nne kuu za muundo: ncha kali, mfuniko, utandao, na nucleocapsid.