Human herpesvirus 7 integrates into host telomeres via its telomeric repeat arrays

Human herpesvirus 7 (HHV-7) is a widespread human betaherpesvirus infecting the majority of the global population. Despite its clinical relevance and its unique ability to establish lifelong persistence, HHV-7 has remained poorly understood.

Some herpesviruses, like human herpesvirus 6 (HHV-6) and Marek's disease virus (MDV), carry telomeric repeat arrays within their genomes, allowing them to exploit host telomeres as integration sites during latency. HHV-7 also contains telomeric repeat sequences, but direct evidence for telomere-mediated integration had remained elusive.

In this study, we established a bacterial artificial chromosome (BAC)-based genetic system for HHV-7, enabling stable cloning, genetic engineering, and efficient reconstitution of infectious virus. This platform provides new opportunities to investigate viral replication, host interaction, latency, and chromosomal integration mechanisms at the molecular level. Furthermore, the system enables targeted mutagenesis and functional characterization of viral genes that were previously difficult to study in HHV-7.

Beyond advancing fundamental herpesvirus biology, this work provides an important technological foundation for future antiviral research, synthetic virology approaches, and comparative studies of human betaherpesviruses. By creating a genetically tractable HHV-7 model, the study contributes valuable tools and knowledge to the broader fields of virology, infection biology, and translational biomedical research.