VIRION
Enveloped, spherical. Diameterabout 130nm.
GENOME
Segmented Negative-stranded RNA linear genome, L segment is about 6.8kb, M segment about 4.1kb and S segment about 1.3kb. Encodes for three proteins.
GENE EXPRESSION
Transcription is made in cytoplasm by viral RNA dependent RNA polymerase (L) binding to a promoter on each encapsidated segment.
ENZYMES
REPLICATION
CYTOPLASMIC
- Virus attaches to host receptors though Gn-Gc glycoprotein dimer, and is endocytosed into vesicles in the host cell.
- Fusion of virus membrane with the vesicle membrane; ribonucleocapsid segments are released in the cytoplasm.
- Transcription, viral mRNAs are capped in the cytoplasm.
- Replication presumably starts when enough nucleoprotein is present to encapsidate neo-synthetized antigenomes and genomes.
- The ribonucleocapsids buds at Golgi apparatus, releasing the virion by exocytosis.