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

우리나라에서 분리된 풍진바이러스의 염기서열 분석 및 유전자 발현

During the recent epidemic period ($1995{\sim}1996$), 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 $95.8{\sim}98.1%$, $92.6{\sim}99.2%$ and $96.4{\sim}99.3%$ based on 1,441, 122 and 139 nucleotides and $96.9{\sim}98.5%$, $90{\sim}100%$ and $97.8{\sim}100%$ 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 $91.5{\sim}92.1%$, $83.6{\sim}88.5%$ and 91.4% based on nucleotides and $96.9{\sim}97.7%$, 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 cosmopolitan and Asian types formed two 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.