伪狂犬病病毒Ea株基因组UL区的克隆与序列分析

从伪狂犬病病毒Ea株基因组DNA中扩增到3．76kb的基因组片段，该片段包含UL31、UL32、UL33和UL34基因完整编码区，以及UL30和UL35基因部分序列。UL31、UL32、UL33和UL34基因G C含量为69．5％～73．4％，偏向于使用富含GC特别是第三密码子位置上核苷酸是C或G的密码子，Ala、Leu、Arg的利用率最高，占氨基酸残基总数的36．4％。PRV Ea株UL31和UL32基因与PRV Ka株核苷酸与氨基酸序列同源性都很高，在98％以上；而UL33和UL34基因与Ka株的氨基酸序列同源性较低，分别为95．7％和94．8％。UL31基因在疱疹病毒α—亚科所有成员之间都很保守，并且UL31基因与马疱疹病毒IV型同源程度最高。UL32、UL33和UL34基因均与牛疱疹病毒I型同源程度最高。UL31、UL32、UL33与UL34基因产物均有酪蛋白激酶2磷酸化位点和蛋白激酶C磷酸化位点，表明UL31、UL32、UL33、UL34蛋白质可能都是磷酸化蛋白质。

Cloning and Sequence Analysis of the Genome Unique Long Region of Pseudorabies Virus Ea Strain

A 3.76 kb genome DNA fragment, containing the complete coding sequences of UL31, UL32, UL33 and UL34 genes and the partial coding sequences of UL30 and UL35 genes of Pseudorabies virus (PRV) Ea strain, was amplified by PCR and sequenced. The results show that the G C contents of UL31, UL32, UL33 and UL34 genes are varied from 69.5% to 73.4%, and the amino acid composition is skewed to codons rich in Gs and Cs nucleotides, especially the third codon is Cs or Gs. The three most common amino acids (Ala, Leu and Arg) comprise 36.4% of the total residues. Both the nucleotide and amino acid sequences identities of UL31 and UL32 genes of PRV Ea strain and PRV Ka strain are more than 98.2%, whereas the amino acid identities of UL33 and UL34 genes are 95.7% and 94.8%, respectively. The UL31 gene is highly conserved among alphaherpesviruses, and the homology of UL31 gene of PRV and Equine herpesvirus 4 (EHV-4) is higher than others. The amino acid sequence identitie of UL32, UL33 and UL34 genes of PRV and Bovine herpesvirus 1 (BHV-1) are higher than others. Protein kinase C phosphorylation sites and casein kinase II phosphorylation sites are found in all the amino acid sequences of UL31, UL32, UL33 and UL34 genes, which suggests that all the four genes are possibly phosphoproteins.