Human rotaviruses are an important cause of severe diarrhea in young children throughout the world. Rotavirus infections are especially devastating in developing nations because of the high mortality rate associated with gastroenteritis. By the age of 3, the incidence of rotavirus infections decreases markedly, but outbreaks of rotavirus-induced diarrhea have been reported among the elderly, the acutely ill, and the immunocompromised. Other mammals and birds can develop rotavirus diarrhea as well, making this disease one of veterinary interest and economic concern. Effective means of preventing this disease are obviously needed. The rotavirus genome consists of 11 segments of double-stranded RNA. Most of the gene segments appear to be moncistronic and together they encode at least 12 viral polypeptides (VP). The genome is enclosed in a core which is surrounded by a double- shelled capsid. VP3 and VP7 are the major outer shell proteins. VP3 is activated by protease cleavage and is associated with host range, hemagglutination, virulence, and both homotypic and heterotypic neutralization. The glycoprotein VP7 is the primary determinant of serotype specific neutralization. This proposal focuses on defining and characterizing those genetically-determined features of VP3 that are involved in gastrointestinal infection. To accomplish this, we plan to: 1) determine the nucleotide sequence encoding the homotypic and heterotypic neutralizing domains on VP3, 2) compare the gene 4 sequences of various murine rotavirus stains with human or simian strains in an effort to clarify the genetic basis of host range, 3) design and execute a series of genetic experiments to determine whether rotavirus RNA is """"""""infectious,"""""""" 4) develop a strategy to clone full length gene 4 cDNA, and 5) use full length cDNA clones of rotavirus gene 4 in a suitable expression vector to produce a biologically active VP3.
