Identification of human herpesvirus 6 uracil-DNA glycosylase gene.

Uracil-DNA glycosylase encoded in many species functions as a DNA repair enzyme that removes uracil residues from DNA. To investigate the potential function of uracil-DNA glycosylase encoded by human herpes-virus 6 (HHV-6), we sequenced a DNA clone (pSTY09), identified an open reading frame of 765 bp and compared the putative amino acid sequence with other uracil-DNA glycosylases, by computer analysis. The amino acid sequence of HHV-6 had similarities to other uracil-DNA glycosylases, with the highest degree of similarity to those of human cytomegalovirus and Epstein-Barr virus. Two strongly conserved regions in uracil-DNA glycosylase of other species also existed in HHV-6. The gene product which was expressed in Escherichia coli demonstrated uracil-DNA glycosylase activity. This is the first report to identify and characterize the uracil-DNA glycosylase gene in HHV-6.