# Genome Characterisation of Esocid Herpesvirus 1 (EsHV-1)

## TL;DR

Scientists sequenced the genome of Esocid Herpesvirus 1 for the first time, revealing its structure and gene organization.

## Contribution

The first near-complete genome sequence of EsHV-1 is reported, including its unique gene arrangement and potential splicing patterns.

## Key findings

- The EsHV-1 genome is 223,553 bp with a GC-content of 56.47% and is organized into two unique segments.
- The genome contains 144 open reading frames, including eight duplicated genes within inverted repeats.
- Alternate splicing patterns suggest a possible role in terminase assembly at the capsid portal.

## Abstract

The alloherpesvirus esocid herpesvirus 1 (EsHV-1) causes epidermal hyperplasia on the skin and fins of northern pike (Esox lucius). For the first time, we present a near-complete genome sequence of EsHV-1, directly obtained from a pike skin sample. The 223,553 bp sequence of the genome has a GC-content of 56.47% and is organised into a long, unique segment (148,159 bp) and a short, unique segment (45,925 bp). The short segment is flanked by inverted repeat sequences (IRSs) of 14,733/6 bp, with the IRS length difference attributed to a codon deletion. The genome is predicted to contain 144 open reading frames, including eight duplicated within the IRSs. The leftmost third of the genome contains genes of unknown function, but many of which exhibit extensive inter-gene homology, suggesting gene duplication. Six paralogous groups were identified, each containing two to thirteen gene members. Homologues of all twelve alloherpesvirus core genes are present. The ATPase subunit of the terminase and the DNA polymerase is composed of three and two exons, respectively. However, an alternate splicing pattern is found, for which, speculatively, a role is suggested in the terminase assembly at the capsid portal.