Analysis on Genetic Characteristics of the Nonstructural Protein NSP4 of Human Rotavirus Strains in Infants with Diarrher in 2007 and 2008 in Kunming

［Abstract］Objective　To study the genetic characteristics and genetic variation of the nonstructural protein NSP4 of Human rotavirus strains．Methods　We selected twelve positive RV samples among 96 infants with diarrhea who were hospitalized in the Department of Peadiatrics，the First Affiliated Hospital of Kunming Medical University from October to December in 2007 and 2008．NSP4 genes was amplified by RT-PCR and then cDNAs were sequenced. The homology of the nucleotide sequences of the NSP4 genes were analyzed by DNA assist and Clustal-mp．Results（1）NSP4 gene was amplifie from 12（6 of 2007 and 6 of 2008）RV positive samples. Among the twelve Kunming strains， the nucleotide homologies of the ten Wa strains to the four HRV standard strains （Wa，KUN，AU-1 and Hochi）and three animal RV（ EW，OSU and All）were 96.3%，85.3%，84.7%， 95.1% and 57.7%，92%，82.8%．Compared with the epidemic strains in other different areas of China， the nucleotide homology of the NSP4 gene was over 95%．Compared with the standard strains from the above GenBank Database，the nucleotide homology of the two KUN strain were 85.3%，98.2%，82.8%，85.9% and 60.1%， 85.3%，94.3%．And compared with the epidemic strains other different areas of China， the nucleotide homology of the NSP4 gene was about 85%.（2）6 unique conserved amino acids of 10 Wa strains differing from Wa at aa34， aa76，aa141，aa161 and aa169 were identified within NSP4; 2 unique conserved amino acids of 2 KUN strains differing from KUN at aa87 and aa140 were identified within NSP4．Conclusions　Among the NSP4 of the twelve Kunming strains，the genotypes are Wa strain and KUN strain．The most dominant genotype of NSP4 is Wa strain