[Analysis on nucleoprotein gene sequence of 25 rabies virus isolates in Guizhou Province, China]

To analyze 25 nucleoprotein gene (N gene) sequences of rabies viruses circulating in Guizhou province during 2005-2010, China, and to explore the epidemic characteristics and the probable mutant of rabies in Guizhou Province. Rabies virus RNA in human brain tissues, human saliva, and domestic dog brain tissues derived from different prefectures of Guizhou Province were detected with RT-nested PCR, and the amplified products were then sequenced. Bioinformatics software was used to determine the genetic characteristics of these rabies viruses. The sequences of N gene of 25 Guizhou provincial isolates were identical with homogeny between 97.5% - 99.3% and 98.4% - 99.8% at nucleotide and deduced amino acid level, respectively, while the identities between them and isolated strains from other province of China were 88% - 99.1% and 88% - 99.7%. There were several amino acid substitutions in the nucleoprotein of 25 Guizhou isolates compared with the known genotype 1 isolates. The analysis of phylogenetic tree of 25 Guizhou isolates was demonstrated to be genetically divided into two groups, indicating that the virus presented a unique characteristics in geographic distribution and in a time dependent-manner. And phylogenetic tree of 25 Guizhou isolates and 7 genotype 1 strains isolated from other Province of China was also divided into two groups, which were further composed of several subgroups, respectively. From these observations, the rabies viruses derived from Guizhou province were still genotype 1. These isolates of rabies virus were diverged from the strains isolated from other provinces in both gene sequences and deduced amino acid sequences, and these divergences were characterized in geographic distribution and in a time-dependent manner.