Viral Replication Complexes Are Targeted by LC3-Guided Interferon-Inducible GTPases

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Viruses with positive-sense RNA genomes utilize cytoplasmic replication complexes (RCs) for replication.
• The host immune system's mechanisms for counteracting viral RCs are not fully understood.

Purpose of the Study:

• To investigate how the host immune system, specifically interferon-gamma (IFNG), disrupts viral replication complexes (RCs).
• To identify the host factors involved in the IFNG-mediated disruption of MNV RCs.

Main Methods:

• Utilized murine norovirus (MNV) as a model system.
• Investigated the role of autophagy proteins (LC3 conjugation system) and IFN-inducible GTPases (IRGs, GBPs) in RC disruption.
• Assessed the impact of IFNG induction on RC integrity and viral replication in vitro and in vivo.

Main Results:

• IFNG disrupts MNV RCs through conserved autophagy proteins and induced IFN-inducible GTPases.
• The MNV RC is marked by the LC3 conjugation system and targeted by IRGs and GBPs.
• Both the LC3 system and IFN-inducible GTPases are essential for inhibiting MNV replication.

Conclusions:

• Viral RCs can be targeted by a universal immune defense mechanism.
• This mechanism involves autophagy proteins and IFN-inducible GTPases, previously known for targeting other pathogens.
• This conserved pathway provides a novel insight into host antiviral defense against RNA viruses.