Cloning and sequence analysis of gB,gC,gD genes of pseudorabies virus strain Fa

The gB,gC,and gD genes of Pseudorabies Virus(PRV) Fa strain were cloned and sequenced.The nucleotide sequence and its deduced amino acid sequence were analyzed using computer programs.The results revealed that the gB,gC,and gD genes were 2745 bp,1464 bp,and 1215 bp long encoding corresponding to proteins 914,487,and 404 amino acids,respectively.The sequence of nucleotides and predicated amino acids were compared with those of other published PRV strains.The results showed that gB,gC,and gD gene nucleotide sequence homology was 94.9%-99.9%,while the amino acid sequence homology was 91.4%-99.9%.The gB,gC,and gD gene shared highly conserved nucleotides among PRV strains.The molecular phylogenetic tree,based on these three genes,showed that the Chinese PRV isolates and the Korean PRV isolate could be grouped into one evolution branch,while the European and American PRV isolates and the Japanese PRV isolate could belong to another branch.In the former branch,the PRV strains Ea and Fa are so closely related to one another that the homology of these three genes were all above 99.5%.The gB proteins of the Chinese PRV isolates(Ea strain and Fa strain) had an amino acid residue more than the European and American isolates and amino acid substitutions happened primarily in the amino acid residues 50 to 100.In the 186-211 nucleotide sites of gC gene,Ea strain and Fa strain had 21 nucleotides more insertion compared to the European and American isolates.The gD proteins of Ea strain and Fa strain were 2-6 amino acids residues more than other strains.For Fa strain,the tandem repetition number of nucleotides AGGCCC in the gD nucleotides 803 to 837 added up to seven,which was the most among all PRV strains.