FIG. 2.
Structure, integrity, and orientation of the HHV-6 genome following integration of linear (A), episomal (B), or concatemeric (C) viral DNA. For simplicity, only one recombination event with the chromosome's telomeric region, yielding a chromosome ending with the viral genome, is presented. (A) Recombination of linear viral DNA through the (TAACCC)n repeats in DRR results in the loss of the pac2 at the right end of the genome. Recombination within (TAACCC)n of DRL (not shown) would result in the loss of the majority of the genome. Without additional recombination events, these structures would not be compatible with a replication/packaging-competent HHV-6. (B) Recombination of episomal viral DNA would result in two different viral genomic architectures, depending on whether recombination occurred within DRL or DRR. Once again, in the absence of additional recombination events, these structures would not be compatible with a replication/packaging-competent HHV-6. (C) Recombination of concatemeric viral DNA through the (TAACCC)n of one DRL is presented. Considering that the pac1-pac2 junction forms a viral genomic cleavage site provided that two such junctions are present, the possibility exists that a full-length genome could be excised once integrated. Similar conclusions could be drawn if the recombination event were to occur within the DRR (not shown). Please refer to main text for further details.