Different linkages in the long and short regions of the genomes of duck enteritis virus Clone-03 and VAC Strains

Abstract

BackgroundDuck enteritis virus (DEV) is an unassigned member in the family Herpesviridae. To demonstrate further the evolutionary position of DEV in the family Herpesviridae, we have described a 42,897-bp fragment. We demonstrated novel genomic organization at one end of the long (L) region and in the entire short (S) region in the Clone-03 strain of DEV.ResultsA 42,897-bp fragment located downstream of the LOFR11 gene was amplified from the Clone-03 strain of DEV by using 'targeted gene walking PCR'. Twenty-two open reading frames (ORFs) were predicted and determined in the following order: 5'-LORF11-RLORF1-ORF1-ICP4-S1-S2-US1-US10-SORF3-US2-MDV091.5-like-US3-US4-US5-US6-US7-US8-ORFx-US1-S2-S1-ICP4 -3'. This was different from that of the published VAC strain, both in the linkage of the L region and S region, and in the length of the US10 and US7 proteins. The MDV091.5-like gene, ORFx gene, S1 gene and S2 gene were first observed in the DEV genome. The lengths of DEV US10 and US7 were determined to be 311 and 371 amino acids, respectively, in the Clone-03 strain of DEV, and these were different from those of other strains. The comparison of genomic organization in the fragment studied herein with those of other herpesviruses showed that DEV possesses some unique characteristics, such as the duplicated US1 at each end of the US region, and the US5, which showed no homology with those of other herpesviruses. In addition, the results of phylogenetic analysis of ORFs in the represented fragment indicated that DEV is closest to its counterparts VZV (Varicellovirus) and other avian herpesviruses.ConclusionThe molecular characteristics of the 42,897-bp fragment of Clone-03 have been found to be different from those of the VAC strain. The phylogenetic analysis of genes in this region showed that DEV should be a separate member of the subfamily Alphaherpesvirinae.

Evaluation of safety and immunogenicity of duck-plague virus gC/gE double gene deletion

“…Duck plague (DP), also known as duck viral enteritis, is caused by Duck Plague Virus (DPV), which belongs to the Alphaherpesvirinae and Mardivirus genus of the Herpesviridae family (1). The structure of DPV virus from outside to inside is envelope, tegument, capsid and core, capsid is icosahedral, genome is linear double-stranded DNA, DPV genome consists of unique long region (UL), intermediate repeat sequence (IRS), unique short region (US) and terminal repeat sequence (TRS), including 78 open reading frames (ORFs), of which 65 ORFs are located in the UL region, 11 ORFs are located in the US region, and the remaining two ORFs are located in the IRS region and TRS region (1)(2)(3)(4)(5)(6). DPV is a pan-tropic virus that can replicate and proliferate in various tissues and organs of the body, epithelial cells and lymphocytes are its main replication sites, the digestive tract and immune organs of ducks are most severely damaged after DPV infection (7)(8)(9)(10).…”