TELOMERIC SEQUENCES FROM HUMAN-HERPESVIRUS-6 DO NOT MEDIATE NUCLEAR RETENTION OF EPISOMAL DNA IN HUMAN-CELLS

Telomeric repeat sequences (TRS) have been identified close to, but no t at, the genome termini of several lymphotropic herpesviruses, includ ing human herpesviruses 6 and 7 (HHV-6, HHV-7). The functional signifi cance of these motifs remains uncertain. Since telomeric sequences can mediate stable retention of episomal DNA in yeast, we, have tested wh ether the TRS motifs from HHV-6 might mediate a similar function in hu man 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 rete ntion mechanism showed a significant level of nuclear retention. Neith er the HHV-6 TRS motifs, nor human telomeric sequences, mediated nucle ar retention of episomal DNA in human cells.