Human cytomegalovirus regulates host DNA repair machinery for viral genome integrity

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• The DNA damage response (DDR) is crucial for maintaining genome integrity.
• DNA viruses, like cytomegalovirus (CMV), activate DDR pathways during replication.
• How viruses manipulate DDR for their benefit is largely unknown.

Purpose of the Study:

• To investigate the role of CMV protein UL138 in modulating host DDR pathways.
• To understand the mechanisms by which CMV utilizes DDR for viral genome replication and integrity.

Main Methods:

• Analysis of viral genome structural variants in UL138-deficient CMV.
• Investigation of UL138's interaction with host deubiquitinating complexes (USP1) and their targets (PCNA, FANCD2, FANCI).
• Assessment of viral genome replication and integrity upon disruption of UL138 and related DDR pathways.

Main Results:

• CMV protein UL138 modulates host DDR pathways, including those involving USP1-PCNA/FANCD2/FANCI.
• Loss of UL138 leads to viral genome structural variants (inversions, deletions, duplications) indicative of DDR activity.
• UL138 also influences DDR pathways independently of USP1-PCNA/FANCD2/FANCI.
• Disruption of UL138 or these DDR pathways impairs viral genome replication and integrity.

Conclusions:

• CMV protein UL138 is a key viral factor that hijacks host DDR pathways for viral replication and genome maintenance.
• UL138 utilizes both USP1-dependent and -independent DDR mechanisms.
• This study provides mechanistic insights into virus-host DDR interactions and establishes CMV as a model for studying these processes.