Characterization of the DNA polymerase gene of human herpesvirus 6.

The construction of a recombinant bacteriophage lambda library containing overlapping clones covering 155 kbp of the 161-kbp genome of the Ugandan U1102 isolate of human herpesvirus 6 (HHV-6) is described. The use of degenerate-primer polymerase chain reaction allowed the isolation of a DNA probe for the DNA polymerase gene of HHV-6, which was subsequently used to isolate and position the pol gene on the physical map of the viral genome. A 4.4-kbp EcoRI DNA restriction fragment containing the pol gene was isolated and sequenced. The open reading frames flanking the pol gene code for the HHV-6 glycoprotein B gene and the human cytomegalovirus UL53 homolog. This arrangement is different from that seen in the alpha and gamma herpesvirus families, lending further support to the notion that HHV-6 is a member of the beta herpesvirus group.