Rhinovirus VP3

Rhinoviruses have single-stranded positive sense RNA genomes of between 7200 and 8500 nt in length. At the 5' end of the genome is a virus-encoded protein, and like mammalian mRNA, there is a 3' poly-A tail. Structural proteins are encoded in the 5' region of the genome and non structural at the 3' end. This is the same for all picornaviruses. The viral particles themselves are not enveloped and are icosahedral in structure. The viral proteins are translated as a single, long polypeptide, which is cleaved into the structural and nonstructural viral proteins. Human rhinoviruses are the most common viral infective agents in humans and are the predominant cause of the common cold. Human rhinoviruses are composed of a capsid, that contains four viral proteins VP1, VP2, VP3 and VP4. VP1, VP2, and VP3 form the major part of the protein capsid. The much smaller VP4 protein has a more extended structure, and lies at the interface between the capsid and the RNA genome. There are 60 copies of each of these proteins assembled as an icosahedron. Antibodies are a major defense against infection with the epitopes lying on the exterior regions of VP1-VP3.