A herpes simplex virus type 1 mutant lacking the ICP0 introns reactivates with normal efficiency

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Herpes simplex virus type 1 (HSV-1) latency is maintained by the latency-associated transcript (LAT) gene.
• Null mutants of the LAT gene exhibit impaired viral reactivation.
• The LAT gene region overlaps the ICP0 gene and spans approximately 8.5 kb.

Purpose of the Study:

• To investigate the role of specific downstream regions within the LAT gene in HSV-1 reactivation.
• To determine if deletions in the ICP0 introns of the LAT gene affect viral reactivation efficiency.

Main Methods:

• Construction of HSV-1 mutants with deletions in downstream LAT gene regions, specifically the ICP0 introns.
• Assessing viral reactivation efficiency using explant cocultivation assays.

Main Results:

• A mutant with deletions in both ICP0 introns of the LAT gene demonstrated normal reactivation.
• This finding indicates that the downstream regions of the LAT gene are not responsible for the previously observed slow reactivation phenotype of LAT null mutants.

Conclusions:

• The slow or inefficient reactivation phenotype of HSV-1 LAT null mutants cannot be attributed to the downstream regions of the LAT gene, including the ICP0 introns.
• Further research is needed to identify the specific LAT gene elements responsible for regulating viral reactivation.