The herpes simplex virus Us11 open reading frame encodes a sequence-specific RNA-binding protein.

Area of Science:

• Virology
• Molecular Biology
• RNA-protein interactions

Background:

• Herpes simplex virus (HSV) infection involves complex interactions between viral and cellular components.
• Specific RNA-binding activities can play critical roles in viral gene expression and replication.

Purpose of the Study:

• To identify and characterize an RNA-binding activity present in HSV-infected cells.
• To determine the viral gene responsible for this RNA-binding activity.

Main Methods:

• Utilized in vitro transcribed RNA sequences from HSV genes (US11, alpha 47) incubated with infected and uninfected cell extracts.
• Employed RNase digestion to assess RNA protection by bound proteins.
• Analyzed HSV-1 x HSV-2 recombinants and HSV-1 deletion mutants to map the functional gene.
• Performed in vitro translation of US11 mRNA and assessed RNA-binding activity.
• Investigated the effect of C-terminal US11 protein modifications on binding complex mobility.

Main Results:

• An RNA-binding activity was detected in HSV-1 and HSV-2 infected cell extracts, but not in uninfected cells.
• The binding was specific to a sequence derived from HSV-1 US11 and alpha 47 genes and protected ~95 nucleotides.
• Genetic analyses mapped the activity to the US11 or alpha 47 open reading frame, with US11 confirmed as the sole viral requirement.
• In vitro synthesized US11 mRNA produced the RNA-binding activity.
• Modification of the US11 protein's C-terminus affected the binding complex's mobility, indicating US11 protein association.

Conclusions:

• The US11 gene product of herpes simplex virus is responsible for a specific RNA-binding activity.
• This RNA-binding activity is a late viral function dependent on viral DNA synthesis.
• The US11 protein directly associates with the RNA-binding complex.