Publikationsdatenbank

Human herpesvirus 6:
excision of integrated viral genomes from host telomeres and impact of telomere length on viral integration (2024)

Art

Hochschulschrift

Autor

Aimola, Giulia (WE 5)

Quelle

Berlin: Mensch & Buch Verlag, 2024 — VIII, 112 Seiten

ISBN: 978-3-96729-269-5

Sprache

Englisch

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/46885

Kontakt

Institut für Virologie

Robert-von-Ostertag-Str. 7-13
14163 Berlin
+49 30 838 51833
virologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Human herpesviruses 6A and 6B are two closely related betaherpesviruses with the ability to integrate their genomes into the host chromosomes, establish a latent infection and persist in the host for life. These viruses can also infect germ cells and be inherited by the offspring, resulting in individuals who harbor the integrated virus in every cell of their body. This condition is termed inherited chromosomally integrated HHV-6A/B (iciHHV-6A/B). However, Integration must not be seen as a dead end for the virus, as it can be released from the chromosome and start a new lytic infection, resulting in different clinical manifestations. The currently available pharmacological treatments can only partially reduce the viral replication and counteract the clinical symptoms. Unfortunately, until now we have neither a way to prevent the viral reactivation nor get rid of the integrated virus. Here we provide the first proof-of-concept that integrated HHV-6A genomes can be successfully removed in vitro from the host chromosomes using CRISPR/Cas9 system and specific guide RNAs targeting the direct repeats of the viral genome. The successful genome removal was achieved in latently infected cells generated in vitro, as well as in iciHHV-6A patient cells, and confirmed using three different techniques: flow cytometry, quantitative PCR (qPCR), and fluorescence in situ hybridization (FISH) analyses. Our results open the road to possible future clinical applications and provide an additional research tool to further investigate different aspects of HHV-6A biology in vitro. As for many other aspects of HHV-6A/B, the integration process still needs to be fully understood and many questions remain unanswered. HHV-6A/B does not randomly integrate into the host chromosomes, but specifically into the telomeres. We know that the viral telomeric repeats play an essential role, and this aspect raises the question whether the host telomeres length also plays a role in this process. With this question in mind, we developed a method to measure the telomere length by quantitative fluorescence in situ hybridization, confocal microscopy, and computational processing. Our findings suggest that the integration can occur regardless of the telomere length and the integration process itself seems not to have a Major short-term effect on the telomere length. The data generated in the two works presented in this thesis, collectively represent a further step towards a better understanding of HHV-6A/B biology.