PRV LA株gD基因的序列测定及其重复高变区的发现

对猪伪狂犬病病毒鲁A株(PRVLA株)gD基因进行了克隆和序列测定，结果表明：在测序的l453bp的DNA序列中包括着1个l203bp的ORF(即gD基因)，它编码400个氨基酸组成的多肽；在整个gD基因的ORF内PRVLA株与PRV Ea株、Hulbei株、Rice株、NIA-3株、Kaplan株的gD基因比较，核苷酸的同源性分别为98．3％、98．3％、98．0％、98．1％、98．6％，氨基酸的同源性分别为97．8％、97．8％、97．5％、98．1％、98．6％；发现PRVLA株gD基因与Ea株、Hubei株、Rice株、NIA-3株、Kaplan株的gD基因均在802～837nt处有1个C(A)GGCCC的重复高变区，其对应的是gD267～279位氨基酸残基Arg—Pro的重复高变区。正是该重复高变区的碱基缺失或插入使得PRVgD的ORF在l194～l215nt间变化，gD前体的氨基酸残基为398～404个。

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.