Genome Sequence of Canine Herpesvirus

Abstract

Canine herpesvirus is a widespread alphaherpesvirus that causes a fatal haemorrhagic disease of neonatal puppies. We have used high-throughput methods to determine the genome sequences of three viral strains (0194, V777 and V1154) isolated in the United Kingdom between 1985 and 2000. The sequences are very closely related to each other. The canine herpesvirus genome is estimated to be 125 kbp in size and consists of a unique long sequence (97.5 kbp) and a unique short sequence (7.7 kbp) that are each flanked by terminal and internal inverted repeats (38 bp and 10.0 kbp, respectively). The overall nucleotide composition is 31.6% G+C, which is the lowest among the completely sequenced alphaherpesviruses. The genome contains 76 open reading frames predicted to encode functional proteins, all of which have counterparts in other alphaherpesviruses. The availability of the sequences will facilitate future research on the diagnosis and treatment of canine herpesvirus-associated disease.

Fig 1. Map of the CHV/0194 genome.

ORFs are shown by coloured arrows, with names below. Red shading shows ORFs that were inherited from the ancestor of family Herpesviridae, blue shading shows ORFs that were inherited from the ancestor of subfamily Alphaherpesvirinae, and orange shading shows ORFs that evolved within subfamily Alphaherpesvirinae. Inverted repeats TR_S/IR_S are shaded yellow, and inverted repeats TR_L/IR_L are shown by green vertical lines. Tandem repeats are marked by grey shading, and origins of DNA replication by vertical red lines.

Fig 2. Phylogenetic tree of varicellovirus DNA polymerases.

The tree was rooted on HSV1, which is a member of genus Simplexvirus. Bootstrap values are indicated at nodes as fractions. The scale bar indicates substitutions per amino acid residue.