SUN2 Modulates the Propagation of HSV-1

Area of Science:

• Cell Biology
• Virology
• Molecular Biology

Background:

• Herpesviruses egress the nucleus via a unique pathway, budding through nuclear membranes due to their large size, exceeding nuclear pore capacity.
• The perinuclear space, where enveloped virions transiently exist, is narrower than the viral particles, necessitating nuclear membrane adjustments.
• The linker of the nucleoskeleton and cytoskeleton (LINC) complex, comprising SUN and KASH proteins, regulates nuclear envelope structure and spacing.

Purpose of the Study:

• To investigate the role of SUN proteins, inner nuclear membrane components of the LINC complex, in the propagation of herpes simplex virus 1 (HSV-1).
• To determine if HSV-1 interacts with the LINC complex similarly to other herpesviruses like pseudorabies virus and human cytomegalovirus.

Main Methods:

• Utilized dominant-negative SUN mutants to disrupt LINC complex function.
• Employed RNA interference (RNAi) to specifically reduce SUN protein levels.
• Quantified HSV-1 extracellular viral yields following LINC complex perturbation.

Main Results:

• HSV-1 propagation was found to be dependent on the LINC complex.
• Disruption of SUN2, but not SUN1, using dominant-negative mutants or RNAi, resulted in significantly increased HSV-1 extracellular viral yields.
• The virus appears to modulate perinuclear spacing during its replication cycle.

Conclusions:

• SUN2 exhibits an antiviral effect against HSV-1, contrary to findings for other herpesviruses.
• The LINC complex, particularly SUN2, plays a critical role in regulating HSV-1 egress and replication.
• Differences in host-pathogen interactions among herpesviruses are highlighted, emphasizing virus-specific dependencies on cellular machinery.