Analysis on nucleoprotein gene of wild measles virus isolated in Dongguan, Guangdong province

Objective To analyze the sequence of nucleoprotein gene of a wild measles virus strain isolated in Dongguan in 2008, learn about the genotype of the strain and the mutation of the nucleoprotein gene.Methods Urine specimens were collected from measles cases during an outbreak, the virus was isolated by inoculating the urine specimens to Vero-Slam cell line.The COOH-terminal of nucleoprotein gene was amplified by RT-PCR, the expected length of the fragment was 594 bp.PCR products were purified, sequenced and the 450 bp COOH-terminal of nucleoprotein gene fragment was compared with reference strains of wild measles virus and Shanghai 191 vaccine strain, than phylogenetic tree was constructed.Results Phylogenetic analysis of the N gene sequences showed that the isolate belonged to H1 genotype H1a subtype.the virus had 99.1%, 97.1%, 97.6%-98.0% and 92.9% homology of nucleotides sequence with China93-2 virus, China 94-7 virus, other H1 genotype virus and Shanghai191 vaccine strain virus respectively.Conclusion The measles virus isolated during the outbreak belonged to H1 genotype H1a subtype, which was similar to the virus in other part of China and had small diversity of nucleotides sequence with same subtype virus.