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

Abstract

To investigate the genetic characteristics and variation within the phosphoprotein (P) gene of measles epidemic strains circulated in Zhejiang province. 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. 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. The variation within the P gene between the vaccine and epidemic strains circulated in Zhejiang province during 1999 to 2008 was significant.