Comprehensive Analysis of Equid Herpesvirus Recombination: An Insight Into the Repeat Regions

• Published in: Journal of equine veterinary science 2023-11, Vol.130, p.104916-104916, Article 104916
• Main Authors: Tau, Rocío Lucía, Ferreccio, Carola, Bachir, Natalia, Torales, Fatima, Romera, Sonia Alejandra, Maidana, Silvina Soledad
• Format: Article
• Language: English
• Subjects: Alphaherpesvirus; Equid herpesvirus; Homologous recombination; Infected cell protein 4
• ISSN: 0737-0806; 1542-7412
• DOI: 10.1016/j.jevs.2023.104916

•New recombinant breakpoints are described for EHV-1 and EHV-8 strains.•Interspecific events of recombination distributes mostly at the repeat regions.•ICP4 is a hotspot for recombination in equid alphaherpesvirus.•Immediately early genes seems to be a primary target for recombination.•EHV1 zebra borne genotypes recombine at different locations with EHV-9. High-throughput sequencing of genomes has expanded our knowledge of the Alphaherpesvirinae, a widely extended subfamily of DNA viruses that recombine to increase their genetic diversity. It has been acknowledged that equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4), two alphaherpesviruses with an economic impact on the horse industry, can recombine. This work aimed to analyze interspecific recombination between all equid alphaherpesvirus species, using genomes of EHV-1, EHV-3, EHV-4, EHV-6, EHV-8, and EHV-9 available in GenBank. 14 events of recombination by RDP4 and Simplot between EHV-1 x EHV-4, EHV-1 x EHV-9, EHV-8 x EHV-1, and EHV-8 x EHV-9 were identified. Ten out of 14 events involved ORF64, a double-copy gene located at the repeat regions that codifies for the infected cell protein 4 (ICP4). Among the ICP4, recombination can be found between EHV-1 X EHV-9, EHV-8 X EHV-9, and EHV-1 X EHV-4, the former affects zebra-borne genotypes, a type of EHV-1 that infect wild equids, and the latter match with previous breakpoints reported in fields isolates. Consequently, these findings strongly suggest that ICP4 is a hotspot for recombination. This work describes novel recombination events and is the first genome-wide recombination analysis using all available equid alphaherpesvirus species genomes.