鸭肠炎病毒UL6基因的分子特征

为了研究鸭肠炎病毒(Duck enteritis virus,DEV)UL6的特征,以DEV Clone-03株基因组DNA为模板,用靶基因步移PCR方法扩增得到UL6基因区域2534 bp的DNA片段。结果发现,DEV Clone-03 UL6基因由2373个核苷酸组成,编码一条790个氨基酸残基组成的多肽。与14株已报道的具有全UL6同源基因序列的疱疹病毒参考株进行比较,DEV Clone-03株与α疱疹病毒的核苷酸和氨基酸同源性较之与β疱疹病毒和γ疱疹病毒要高。氨基酸序列比较显示,DEV Clone-03 UL6基因具有α疱疹病毒UL6同源基因5个保守区域。UL6基因推导的氨基酸系统发育进化树分析发现,DEV Clone-03与α疱疹病毒属一个群,在α疱疹病毒中与马立克氏病病毒(Marek′sdisease herpesvirus,MDV)更接近。同时,序列分析发现,在201~222和425~441等氨基酸位,α疱疹病毒参考毒株均有不同程度的缺失,而DEV Clone-03表现出独有的完整性。

Molecular Characterization of UL6 Gene of Duck Enteritis Virus

Previous report has indicated that UL6 protein of herpes simplex virus 1(HSV-1) is essential for the cleavage and packaging of the viral genome.To identify the features of DEV UL6,the "targeted gene walking PCR" was used to amplify the UL6 open reading frame(ORF) of the DEV Clone-03,and a 2,534 bp DNA fragment was obtained,which covers the entire DEV UL6 gene of the DEV Clone-03 genome.The UL6 ORF of DEV Clone-03 was composed of 2373 nucleotides encoding for a polypeptide of 790 amino acid residues.Sequence comparison of UL6 homologies among DEV Clone-03 and 14 reference herpesvirus strains showed that DEV Clone-03 was more homologous to alphaherpesviruses than to betaherpesviruses or gammaherpesviruses.A clustered alignment of amino acid sequences showed that the UL6 of DEV Clone03 had five conserved regions as that among alphaherpesviruses.Phylogenetic analysis showed that DEV Clone-03 was clustered into the group of alphaherpesvirus and was more similar to Marek's disease herpesvirus(MDV) than to others.Furthermore,homology analysis of deduced amino acid sequences of UL6 homologous genes showed that although there were a range of amino acid deletions among the reference alphaherpesviruses at positions 201-222 and 425-441,these residues were well conserved in DEV Clone-03.