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Updated: May 3, 2026
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Dissecting Host-virus Interaction in Lytic Replication of a Model Herpesvirus
Published on: October 7, 2011
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A viral APOBEC3 antagonist distinguishes HHV-6A from HHV-6B
Jun Arii1,2, Salma Aktar3,4,5, Jing Rin Huang3
1Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan. jarii@med.kobe-u.ac.jp.
Nature Communications
|May 1, 2026
Summary
Human herpesvirus 6A is restricted by APOBEC3 enzymes, unlike HHV-6B. HHV-6B evades this restriction using its U28 protein, influencing viral evolution and disease.
Area of Science:
- Virology
- Immunology
- Genetics
Background:
- Human herpesviruses (HHVs) display varied disease outcomes, with underlying molecular mechanisms often unclear.
- Human herpesvirus 6B (HHV-6B) is linked to exanthema subitum and encephalitis, whereas HHV-6A is generally asymptomatic.
Purpose of the Study:
- To investigate the differential impact of cellular APOBEC3 enzymes on HHV-6A and HHV-6B replication.
- To elucidate the molecular basis for HHV-6B's ability to evade APOBEC3 restriction.
Main Methods:
- Comparative analysis of APOBEC3 enzyme activity against HHV-6A and HHV-6B.
- Investigation of the role of the HHV-6B U28 protein in counteracting APOBEC3.
- Genome sequencing of viral DNA from cell cultures and patients to assess mutation rates.
Main Results:
- Cellular APOBEC3 enzymes restrict HHV-6A replication but not HHV-6B.
- HHV-6B expresses higher levels of U28 protein, which targets APOBEC3 proteins for degradation.
- HHV-6A exhibits extensive viral genome mutations due to failed APOBEC3 counteraction, while HHV-6B shows fewer mutations.
- Ablation of APOBEC3 genes enhances HHV-6A replication and reduces its mutation burden.
Conclusions:
- Differential susceptibility to APOBEC3 restriction significantly impacts HHV-6A and HHV-6B.
- The HHV-6B U28 protein is crucial for evading APOBEC3-mediated antiviral defense.
- These findings suggest a mechanism by which APOBEC3 restriction shapes the distinct clinical presentations and evolutionary potential of HHV-6A and HHV-6B.
