[Rotaviruses: structure and function of the principal polypeptides].

Polypeptides have been defined by studying structural and nonstructural proteins. The rotavirus outer capsid is made up of three proteins: VP7, VP3 and VP9. VP7 is a glycoprotein involved in cell attachment and viral maturation. VP3 is associated with hemagglutination and trypsin activation of virus infectivity; both contain type-specific neutralization determinants. A biological function has not yet been completely defined for VP9. VP6, the main protein of the inner capsid is necessary for mRNA synthesis by the viral transcriptase and determines the subgroup antigenic specificity. These two capsids surround the core which consists of three proteins VP1, VP2, and the product of segment 3, associated with RNA polymerase. Four non-structural polypeptides have been identified (NCVP5, NCVP4, NCVP2, NCVP3); very little is known about their biological role.