This report desoribes the complete nudeotide sequence of human reovirus (Dearing strain) genome segment S3. Previous studies indicated that this RNA encodes the major non-structural viral polypeptlde sigma NS, a protein that binds ssRNAs (Huisman 4 Joklik, Virology 70, 411-421, 1976) and has a poly(C)dependent poly(G) polymerase aotivity (Gomatos e_t al., J. Virol. 2£, 115-124, 1981). The genom...