title: Characterisation of a human herpesvirus 6 variant A 'amplicon' and replication modulation by U94-Rep 'latency gene'.
abstract: The human herpesvirus 6 (HHV-6) variant A genome has conserved sequences which are signals for initiating lytic replication (origin, 'ori-lyt') and DNA packaging into the virion (pac2/1). Here these are functionally characterised and used to construct a gene-expression amplifiable-vector, an 'amplicon', with applications for gene delivery to lymphoid-myeloid cells or their progenitor stem cells. A minimal efficient ori-lyt for replication was identified which was enhanced in the presence of the imperfect direct repeated DNA domain (IDR). In A variant strains these are arranged as three adjacent repeats with the most divergence in IDR3. Addition of the pac2/1 sequences also enhanced detection of ori-lyt replication and conferred DNA packaging properties, thus, the amplicon could be packaged with 'helper' virus. An HHV-6 specific factor, which inhibits amplicon replication was identified by trans replication assays. This is the U94-Rep 'latency' gene product, which can modulate efficiency of such amplifiable vectors, based on the lytic origin. It could also affect maintenance of viral genomes or vectors during latency.
authors.affiliation: Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel St., London WC1E 7HT, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Turner
authors.forename: Dario
authors.initials: D
authors.lastname: DiLuca
authors.forename: Ursula
authors.initials: U
authors.lastname: Gompels
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D005784:Gene Amplification; D014644:Genetic Variation; D015654:Herpesvirus 6, Human / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D019169:Jurkat Cells; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D015183:Restriction Mapping / Q000379:methods; D013601:T-Lymphocytes / Q000821:virology; D014779:Virus Replication / Q000502:physiology*
chemical_list: D017931:DNA Primers