FIGURE 1.

Human rhinovirus genomic organization, virion structure, and species. (A) The 7.21 kb +ssRNA genome of HRV-16 is comprised of a single open-reading frame encoding 11 gene products, which upon translation into three distinct polyproteins are cleaved by HRV-encoded proteases (2A and 3C). The 5′-end of the genome is capped with a short viral priming protein (VPg) for incorporation during virion assembly and a the 3′-end is polyadenylated. Capsid proteins VP1 and VP4 (^∗) are generally used for phylogenetic analysis. RdRP, RNA-dependent RNA polymerase; UTR, untranslated region. (B) An icosahedral virion structure of HRV with a pentamer structure shown highlighting the external capsid proteins (VP1, VP2, and VP3) organization. VP1 is responsible for receptor engagement and VP4 is located beneath each monomeric unit and is responsible for genomic association with VPg. (C) Three distinct species of human rhinovirus have been identified (HRV-A, HRV-B, and HRV-C). The approximate number of types within each species classification and known receptors of each are shown.