Equine herpesvirus type 1 ORF51 encoding UL11 as an essential gene for replication in cultured cells.

The study focuses on the significance of the gene EHV-1 UL11, a protein in equine herpesvirus type 1, required for the virus’s successful replication in cultured cells.

Introduction

• Equine herpesvirus type 1 (EHV-1) is a virus affecting horses and other equines. It can cause a variety of illnesses including respiratory disease, abortion, neonatal death, and neurological disease.
• This study paid specific attention to the UL11 protein, a 74-amino-acid tegument protein, produced by the ORF51 gene in the EHV-1 genome.
• Previous studies on a different strain of EHV-1 virus suggested of UL11 being nonessential for the virus’s replication.

Methodology

• Researchers constructed a variety of UL11 mutant viruses in order to study their behaviour. These mutants included a null mutant where the whole UL11 protein was missing, and a series of truncated mutants wherein parts of the C-terminal of the protein were missing.
• The truncation was done using bacterial artificial chromosome (BAC) technology based on the strain Ab4p.

Findings

• In accordance with previous research, they observed that EHV-1 Ab4p UL11 was located in areas close to the nucleus and Golgi regions.
• More importantly, the study found that the mutant viruses that lacked UL11 or parts of UL11 were unable to produce any offspring viruses when tested on fetal equine kidney cells and rabbit kidney (RK-13) cells.
• Only the mutant virus variants in which RK13-UL11 cells that were constitutively expressing EHV-1 UL11 were able to generate offsprings.

Conclusion

• The study thus contradicts the earlier belief that UL11 was nonessential for viral replication. It shows that UL11 gene of EHV-1 Ab4p is essential for the replication of the virus in cultured cells, reinforcing its significance in the life cycle of EHV-1.