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.