Herpes simplex-1 DNA polymerase. Identification of an intrinsic 5'----3' exonuclease with ribonuclease H activity.

The herpes simplex virus-1 DNA polymerase is a heterodimer of Mr 190,000 which consists of the products of the UL30 (Pol) and UL42 genes. The 136-kilodalton Pol gene product contains an intrinsic ribonuclease H activity that specifically degrades RNA.DNA heteroduplexes or duplex DNA substrates in the 5'----3' direction. It can therefore catalyze the excision of the RNA primers that initiate the synthesis of Okazaki fragments at a replication fork during herpes DNA replication.