[Genetic variation of phosphoprotein (P) gene from measles epidemic strains in Zhejiang province].

ABSTRACT

OBJECTIVE: To investigate the genetic characteristics and variation within the phosphoprotein (P) gene of measles epidemic strains circulated in Zhejiang province. METHODS: The whole sequence of P gene of the epidemic strains related to Zhejiang Measles virus during 1999 to 2008 was amplified, using the RT-PCR Assay. PCR products were sequenced and compared with the sequences of measles vaccine and other epidemic strains. RESULTS: Totally, 1524 nucleotides were sequenced from each epidemic strain and 507 amino acids were derived correspondingly. Compared with the vaccine strain, there were 59 - 75 nucleotides (divergent ratios were 3.9% - 4.9%) mutated from the epidemic strains, which were isolated during 1999 to 2008 and causing mutation on 36 - 42 amino acid (divergent ratios were 7.1% - 8.3%). Changes were also observed on the secondary structure. The phylogenetic tree, constructed based on the sequences of P gene, was similar to that based on the N gene, recommended by WHO. In addition, the average divergent ratio of P protein was greater than the ratio occurred on the N and H genes. CONCLUSION: The variation within the P gene between the vaccine and epidemic strains circulated in Zhejiang province during 1999 to 2008 was significant.