Sequence Analysis of Rubella Viruses Isolated in Korean and Expression of Rubella Specific Gene

ABSTRACT

During the recent epidemic period (1995~1996), seven strains of rubella virus were isolated in Korea. To analyze phylogenetic relationship between seven Korean strains and rubella virus strains from other different geographical areas, structural genes (E1, E2 and C) of Korean strains were enzymatically amplified and automatically sequenced. The sequence similarities of the E1, E2 and C genes of the cosmopolitan types were 95.8~98.1%, 92.6~99.2% and 96.4~99.3% based on 1,441, 122 and 139 nucleotides and 96.9~98.5%, 90~100% and 97.8~100% based on 480, 40 and 46 amino acids compared to the sequences of strain RA27/3, respectively. In contrast, the sequence similarities of the E1, E2 and C genes of the Asian types were 91.5~92.1%, 83.6~88.5% and 91.4% based on nucleotides ad 96.9~97.7%, 85.5% and 97.8% based on amino acids compared to the sequences of strain RA27/3. respectively. However, immunodominent epitopes of the E1 gene of the cosmopolitan and Asian types were well conserved, and the growth patterns in cell culture and immunofluorescent antibody titers in cross-reaction test showed no differences between two different types. In phylogenetic analysis based on nucleotide sequences of each gene regions, the comopolitan and Asian types formed tow distinct phylogenetic lineages. These data showed two distinct genotypes of rubella viruses cocirculated in Korea, but no significant differences in the antigenicity of two different rubella virus strains were found.