Encapsidates the genomic RNA, protecting it from nucleases. Displays high affinity for single-stranded nucleic acid. The encapsidated genomic RNA is termed the nucleocapsid (NC) or ribonucleoprotein. The ribonucleoprotein has a non-helical structure. Serves as template for viral transcription and replication. After replication, the nucleocapsid is recruited to the host Golgi apparatus by glycoprotein Gn for packaging into virus particles 