Cellular antibody affinity-based CRISPR Screening identifies JUNB as a broadly acting anti-viral factor

Area of Science:

• Virology
• Molecular Biology
• Immunology

Background:

• CRISPR screening is vital for identifying genes affecting viral infections.
• Existing virus-focused CRISPR screens have limitations in identifying all relevant host factors.
• Human Cytomegalovirus (HCMV) infection relies on complex cellular interactions.

Purpose of the Study:

• To develop a novel, scalable CRISPR screening pipeline for identifying cellular determinants of HCMV infection.
• To investigate the role of the HCMV UL26 protein in modulating host antiviral responses.
• To uncover host factors critical for controlling HCMV replication and pathogenesis.

Main Methods:

• Development of a novel CRISPR screening pipeline termed VIRCAA (virally induced remodeling of cellular antibody affinity).
• Application of the VIRCAA pipeline to identify cellular genes impacting HCMV infection across its life cycle.
• Interrogation of proteomic and transcriptomic data linked to the HCMV UL26 protein.

Main Results:

• The VIRCAA pipeline successfully identified cellular genes influencing HCMV infection.
• JUNB was identified as a key antiviral factor that drives antiviral gene expression and protein ISGylation.
• HCMV UL26 protein interacts with JUNB, suppressing its nuclear condensation and viral DNA replication compartments.

Conclusions:

• The VIRCAA pipeline is a powerful and scalable tool for discovering host factors in viral infections.
• JUNB plays a significant role in antiviral defense against HCMV and other viruses.
• HCMV UL26 antagonizes JUNB-mediated antiviral immunity, highlighting a critical host-pathogen interaction.