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The KSHV ORF20 Protein Interacts with the Viral Processivity Factor ORF59 and Promotes Viral Reactivation
D Hoffman1, W Rodriguez1, D Macveigh-Fierro1
1Microbiology Department, University of Massachusetts Amherst, Amherst, Massachusetts, USA.
Microbiology Spectrum
|June 9, 2021
Summary
Kaposi's Sarcoma-associated herpesvirus (KSHV) ORF20 protein is crucial for viral DNA replication and virion production during lytic reactivation. This study identifies ORF20's interaction with ORF59, highlighting its role in regulating KSHV lytic replication.
Area of Science:
- Virology
- Molecular Biology
- Cellular Biology
Background:
- Kaposi's Sarcoma-associated herpesvirus (KSHV) undergoes lytic reactivation, leading to viral DNA (vDNA) amplification and nuclear reorganization.
- Viral replication compartments form as sites for vDNA production, involving spatial remodeling and protein relocalization.
- The mechanisms governing nuclear landscape changes during KSHV replication are not fully understood.
Purpose of the Study:
- To investigate the function of KSHV ORF20, a conserved lytic gene, in viral replication.
- To identify proteins interacting with ORF20 during KSHV lytic infection.
- To elucidate ORF20's role in vDNA replication and virion formation.
Main Methods:
- Proximity labeling (biotin ligase) to identify ORF20's proximal interactome.
- Coimmunoprecipitation and immunofluorescence assays to confirm protein interactions and localization.
- Generation of an ORF20-deficient KSHV for comparative replication studies.
Main Results:
- ORF20 interacts with ORF59, the KSHV DNA processivity factor, within replication compartments.
- ORF20-deficient KSHV exhibits significantly diminished virion production and reduced viral late gene expression.
- A notable decrease in vDNA replication was observed in the absence of ORF20.
Conclusions:
- KSHV ORF20 plays an essential role in regulating vDNA replication during lytic infection.
- ORF20 interacts with key replication proteins like ORF59 within replication compartments.
- ORF20 is critical for efficient virion formation and progression of the KSHV lytic life cycle.
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