McInnes C J, Wood A R, Mercer A A
Moredun Research Institute, Edinburgh, UK.
Virus Genes. 1998;17(2):107-15. doi: 10.1023/a:1026431704679.
A homolog of the vaccinia virus (VAC) interferon resistance gene E3L has been discovered in orf virus strain NZ-2, a parapoxvirus that infects sheep, goats and humans. The gene is located 20 kb from the left terminus of the orf virus genome and is transcribed towards this terminus. RNase protection studies have been used to define the limits of the gene and Northern analysis revealed that it is expressed early in infection. The predicted amino acid sequence of the orf virus protein shares 31% identity (57% similarity) with the VAC E3L protein. Four of the six residues identified as being essential to dsRNA binding in the vaccinia virus protein are conserved in the orf virus protein whilst the other two amino acid changes are conservative substitutions. The orf virus gene has been sequenced in two other orf virus strains which vary markedly in their ability to produce experimental lesions in vivo. Their predicted protein sequences vary by less than 3% from the NZ-2 protein. The recombinant orf virus protein, expressed as a fusion protein in E. coli, bound double-stranded (ds)RNA but not dsDNA, single-stranded (ss)DNA or ssRNA . This is the first demonstration of a VAC E3L-like gene encoded by a parapoxvirus.
在羊痘病毒株NZ - 2（一种感染绵羊、山羊和人类的副痘病毒）中发现了痘苗病毒（VAC）干扰素抗性基因E3L的同源物。该基因位于羊痘病毒基因组左末端20 kb处，并朝着该末端转录。核糖核酸酶保护研究已用于确定该基因的界限，Northern分析表明它在感染早期表达。羊痘病毒蛋白的预测氨基酸序列与痘苗病毒E3L蛋白具有31%的同一性（57%的相似性）。在痘苗病毒蛋白中确定对双链RNA结合至关重要的六个残基中的四个在羊痘病毒蛋白中保守，而其他两个氨基酸变化是保守替换。已对另外两种羊痘病毒株的该基因进行了测序，它们在体内产生实验性病变的能力上有显著差异。它们预测蛋白质序列与NZ - 2蛋白的差异小于3%。在大肠杆菌中作为融合蛋白表达的重组羊痘病毒蛋白结合双链（ds）RNA，但不结合dsDNA、单链（ss）DNA或ssRNA。这是首次证明由副痘病毒编码的VAC E3L样基因。
