Telomeric sequences from human herpesvirus 6 do not mediate nuclear retention of episomal DNA in human cells

Summary

Telomeric repeat sequences (TRS) have been identified close to, but not at, the genome termini of several lymphotropic herpesviruses, including human herpesviruses 6 and 7 (HHV-6, HHV-7). The functional significance of these motifs remains uncertain. Since telomeric sequences can mediate stable retention of episomal DNA in yeast, we have tested whether the TRS motifs from HHV-6 might mediate a similar function in human cells. Several candidate sequences were assessed for their ability to provide nuclear retention to an autonomously replicating vector in rapidly dividing human tissue culture cells, including HHV-6 TRS DNA, as well as telomeric DNA from human cells and sequences from Epstein-Barr virus (EBV). However, only a vector carrying the EBV-derived retention mechanism showed a significant level of nuclear retention. Neither the HHV-6 TRS motifs, nor human telomeric sequences, mediated nuclear retention of episomal DNA in human cells.