Gene Sequence and Mapping Data from Marek's Disease Virus and Herpesvirus of Turkeys: Implications for Herpesvirus Classification

Abstract

SUMMARYPurified DNAs from Marek's disease virus (MDV) and the herpesvirus of turkeys (HVT) were randomly sheared and cloned into the M 13 bacteriophage. Two-hundred and ten MDV and 130 HVT clones were sequenced to give representative samples of the genome sequences. The predicted amino acid sequences from these gammaherpesviruses were compared to known sequences from other herpesviruses using computer analysis. Thirty-five MDV and 24 HVT genes were identified by comparison with varicella-zoster virus (VZV), an alphaherpesvirus. However, only 14 MDV and seven HVT genes, giving generally lower homology scores, were found by comparison with Epstein-Barr virus (EBV), a gammaherpesvirus, indicating that MDV and HVT sequences bear greater similarity to VZV than to EBV sequences. A number of sequences were mapped by hybridizing labelled M13 clones to Southern blots of restriction fragments of MDV or HVT DNA. The results were consistent with the MDV and HVT genomes being collinear with VZV.

DNA sequence and organization of genes in a 5{middle dot}5 kbp EcoRI fragment mapping in the short unique segment of Marek's disease virus (strain RB1B)

“…Recently, Buckmaster et al (1988) identified 35 MDV genes by comparing the translated sequence of random fragments of MDV DNA with the amino acid sequences of known herpesvirus proteins. Most of the genes identified mapped in the UL region and were coUinear with genes of the alphaherpesviruses herpes simplex virus (HSV) and varicella-zoster virus (VZV).…”

Murine herpesvirus 68 is genetically related to the gammaherpesviruses Epstein-Barr virus and herpesvirus saimiri

“…Such an approach has been used previously to determine rapidly the overall conservation of gene order and genetic relatedness of the gammaherpesviruses EBV and HVS (Gompels et al, 1988), and the close genetic relationship of MDV with the alphaherpesviruses VZV and HSV (Buckmaster et al, 1988). We have identified nine genes in MHV-68 which are homologous to the EBV BNRF1, BORF2, major capsid protein (BcLF1), DNA polymerase (BALF5), major DNA-binding protein (BALF2), BXLF1, BVRF1, BVRF2 and BXRF1 reading frames.…”

“…Recent genetic analyses of MDV of chickens (Buckmaster et al, 1988) underline some of the difficulties in predicting the likely biological properties of herpesviruses on the basis of genetic data alone. Although arguments can be brought forward in an attempt to resolve the apparent inconsistencies between the biological and genetic data in the case of MDV (see Introduction to this paper and Honess et al, 1989a) it is clear that our understanding of the correlation between the genetic content of herpesviruses and their biological properties is far from complete.…”

“…It is associated with lymphomas in chickens (Payne, 1982) from which cell lines harbouring multiple copies of methylated virus DNA can be established (Hirai et al, 1981). Yet in terms of both gene content and organization, MDV and its close relative the herpesvirus of turkeys (HVT), are evolutionarily related to the neurotropic alphaherpesviruses HSV and VZV (Buckmaster et al, 1988). From these data one can conclude either that important aspects of the biology of MDV have been overlooked, or that.…”

Open reading frame L1 of Marek's disease herpesvirus is not essential for in vitro and in vivo virus replication and establishment of latency.

“…Marek's disease (MD), a lymphoma of thymus-derived lymphocytes in chickens, is caused by Marek's disease herpesvirus (MDV), which has been classified as an alphaherpesvirus (Buckmaster et al, 1988). MDV DNA consists of a unique long sequence (UL) and a unique short sequence (US) both flanked by a set of inverted repeats (terminal repeat long region, TRL ; inverted repeat long region, IRL ; inverted repeat short region, IRS ; and terminal repeat short region, TRS) ( Fig.…”