title: [Sequence analysis of G glycoprotein gene of human respiratory syncytial virus].
abstract: OBJECTIVE
  To understand the variation of G glycoprotein gene of human respiratory syncytial virus (HRSV) obtained from Sichuan in 2010 and determine the dominant genotypes.
  
  
  METHODS
  G glycoprotein gene of seven cases of subtype A and eleven cases of subtype B of HRSV were amplified by RT-PCR and sequenced. The phylogenetic trees were constructed to determine the subtype of samples. And then, the genetic variations of the second hypervariable region of G glycoprotein gene were studied.
  
  
  RESULTS
  The nucleotide genetic distances of G glycoprotein gene in subtype A and subtype B HRSV were 0.022 +/- 0.005 and 0.073 +/- 0.010, respectively. Transitions were more prevalent than transversions, GA -AG were the most frequent transitions detected among group A viruses, while UC+CU transitions were the most among group B. Phylogenetic analyses demonstrated that 7 subtype A virus could be clustered into one genotype, genotype GA2, and 11 subtype B virus could be clustered into two genotypes, GB2 and BA. The length of G protein gene in group A was all 298aa, but in group B included 295aa, 312aa and 315aa. Selective pressure was purifying selection in both subtypes. 9 positively selected sites in group A and 1 in group B on the second hypervariable region of G protein were identified.
  
  
  CONCLUSIONS
  GA2, GB2 and BA were the main genotype. The changes may favor virus escape from the host immune response including the variation of the G protein gene length, frequency of nucleotide changes and selective pressure.
authors.forename: Meng-Yan
authors.initials: MY
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Cheng
authors.forename: Fan
authors.initials: F
authors.lastname: Chen
authors.forename: Tian-Lin
authors.initials: TL
authors.lastname: Lu
authors.forename: Ze-Feng
authors.initials: ZF
authors.lastname: Dong
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Pei
authors.forename: Xin
authors.initials: X
authors.lastname: Xu
mesh_terms: D005814:Genes, Viral; D014644:Genetic Variation; D005838:Genotype; D010802:Phylogeny; D017354:Point Mutation; D018113:Respiratory Syncytial Virus, Human / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014760:Viral Fusion Proteins / Q000235:genetics*
chemical_list: C502275:G glycoprotein, Respiratory syncytial virus; D014760:Viral Fusion Proteins