THE UL2 OPEN READING FRAME OF BOVINE HERPESVIRUS-1 ENCODES A URACIL-DNA GLYCOSYLASE

Sequence analysis within the unique long segment of the bovine herpesv irus 1 (BHV-1) genome previously identified an open reading frame (ORF ), designated UL2, whose deduced polypeptide of 204 amino acids contai ned a consensus uracil-DNA glycosylase (UDGase) signature sequence. To determine whether the BHV-1 UL2 ORF product has UDGase activity, we p ositioned the UL2 sequence downstream of the T7 promoter on the vector pET-28b(+) and expressed it in Escherichia coil, Upon induction with isopropyl beta-D-thiogalactopyranoside these cells produced a 23-kDa p rotein, the molecular mass of which was in accordance with the predict ion from the nucleotide sequence. A one-step purification procedure us ing nickel-chelating affinity chromatography resulted in a homogeneous preparation of this protein, which displayed specific UDGase activity in an in vitro enzyme assay. These results provide evidence that the BHV-1 UL2 gene does encode a UDGase.