The Telomeric Repeats of HHV-6A Do Not Determine the Chromosome into Which the Virus Is Integrated.

Human herpes virus 6A (HHV-6A) is able to integrate into the telomeric and subtelomeric regions of human chromosomes representing chromosomally integrated HHV-6A (ciHHV-6A). The integration starts from the right direct repeat (DR) region. It has been shown experimentally that perfect telomeric repeats (pTMR) in the DR region are required for the integration, while the absence of the imperfect telomeric repeats (impTMR) only slightly reduces the frequency of HHV-6 integration cases. The aim of this study was to determine whether telomeric repeats within DR may define the chromosome into which the HHV-6A integrates. We analysed 66 HHV-6A genomes obtained from public databases. Insertion and deletion patterns of DR regions were examined. We also compared TMR within the herpes virus DR and human chromosome sequences retrieved from the Telomere-to-Telomere consortium. Our results show that telomeric repeats in DR in circulating and ciHHV-6A have an affinity for all human chromosomes studied and thus do not define a chromosome for integration.