Cloning,Sequencing and a Highly Repeated and Altered Region Analysis of gD Gene of PRV LA Strain

The gD gene of the wild Chinese PRV LA strain was amplified by polymerase chain reaction(PCR).The PCR product was ligated to pGEM T easy vector and the nucleotides of the gD gene was sequenced.An analysis of the nucleotide sequence and its deduced amino acid sequence were performed with computer programs.The results showed that the region of DNA sequenced is 1 453 base pairs and it contains one ORF of 1 203 base pairs encoding a protein of 400 amino acids.The gD gene of PRV LA strain shares highly conserved nucleotide with PRV Ea strain,Hubei strain and NIA 3 strain and Kaplan strain.The homology of deduced amino acids of PRV LA strain with PRV Ea strain,Hubei strain and NIA 3 strain and Kaplan strain is 97 8%,97 8%,97 5%,98 1%,98 6%,respectively.But the PRV gD genes shared limited homology to other alphaherpesviruses equivalents:BHV 5,EHV 1,FHV 1,CaHV 1,MDV,HVT,ILTV,HSV 1,HSV 2 and SHBV.The nucleotide sequence analysis of the 6 PRV strains revealed that there was a highly repeated and altered region which laid to 802 837 nt in their nucleotide sequences corresponding to their amino acid sequences 267 279,the insertion and deletion of nucleotides in the region made the gD gene variable between 1 194 1 215 nt.