- This page is for the virus. For the disease, see Rubella.
Rubella virus is an enveloped, single-stranded RNA virus and the only member of the genus Rubivirus within the Togaviridae family. The virus has an average diameter of 58 nM and an icosahedral nucleoprotein core 30 nM in diameter. Glycoprotein "spikes", 5–8nM long, are embedded in the lipoprotein enevlope. The Rubella virus genome consists of a single strand of RNA which is 9,762 nucleotides long. It is capped at the 5' end and polyadenylated at the 3' end, and encodes 5 genes.
The virus particle, or virion
, is enveloped
and approximately 60nm in diameter. The surrounding envelope is derived from the host cell membrane and viral glycoproteins
that form projections approximately 6nm long.
The virion consists of a single polyadenylated
molecule of RNA
enclosed in a nucleocapsid
Rubella virus replicates in the cytoplasm of host cells. The viral genomic RNA serves as a template for the synthesis of negative sense RNAs which are used to produce cytoplasmic messenger RNA (mRNA
). The mRNAs direct the production of viral proteins and are also packaged as genomic RNA in virions.
The viral RNA has two open reading frames (ORFs) and untranslated regions (UTRs) at the 5' and 3' ends of the genome.
The virus contains three glycosylated, membrane-
associated proteins, El,
E2a and E2b, and one unglycosylated nucleocapsid protein, C .