Rubella virus, scientific name Rubivirus rubellae, is a member of the genus Rubivirus and belongs to the family of Matonaviridae, whose members commonly have a genome of single-stranded RNA of positive polarity which is enclosed by an icosahedral capsid.

This family is named after George de Maton, who in 1814 first distinguished rubella from measles and scarlet fever.

[3] The change was made by the International Committee on the Taxonomy of Viruses (ICTV), the central governing body for viral classification.

There are prominent "spikes" (projections) of 6 nm composed of the viral envelope proteins E1 and E2 embedded in the membrane.

[6] The E1 glycoprotein is considered immunodominant in the humoral response induced against the structural proteins and contains both neutralizing and hemagglutinating determinants.

Further is it responsible for the aggregation of RNA in the capsid, it interacts with the membrane proteins E1 and E2 and binds the human host-protein p32 which is important for replication of the virus in the host.

[9] As opposed to alphaviruses the capsid does not undergo autoproteolysis, rather is it cut off from the rest of the polyprotein by the signal-peptidase.

[11] The genome encodes several non-coding RNA structures; among them is the rubella virus 3' cis-acting element, which contains multiple stem-loops, one of which has been found to be essential for viral replication.

[12] The only significant region of homology between rubella and the alphaviruses is located at the NH2 terminus of non structural protein 3.

The sequences for the structural proteins are first replicated by the viral RNA polymerase (Replicase) via a complementary −ssRNA as a template and translated as a separate short mRNA.

E1 and E2 are type I transmembrane proteins which are transported into the endoplasmatic reticulum (ER) with the help of an N-terminal signal sequence.