GENOMIC SEQUENCE OF THE RA27 3 VACCINE STRAIN OF RUBELLA-VIRUS/

The sequence of the genome of the RA27/3 vaccine strain of rubella vir us (RUB) was determined. In the process, several discrepancies between the previously reported genomic sequences of two wild RUB strains (Th erien and M33) were resolved. The genomes of all three strains contain 9 762 nucleotides (nts), exclusive of the 3' poly A tract. In all thr ee strains, the genome contains (5' to 3'), a 40 nt 5' untranslated re gion (UTR), an open reading frame (ORF) of 6348 nts that encodes nonst ructural proteins, a 123 nt UTR between the two genomic ORFs, a 3 189 nt ORF that encodes the structural proteins, and a 62 nt 3' UTR. The 5 ' end of the subgenomic RNA was found to correspond to a uridine resid ue at nt 6436 of the genomic RNA. At the nucleotide level, the sequenc e of the three strains varied by 1.0 to 2.8%, while at the amino acid level, the sequence varied by 1.1 to 2.4% over both ORFs. The RA27/3 s equence will be of use in identification of the determinants of its at tenuation, in vaccine production control and in development of second generation RUB vaccines based on recombinant DNA technology.