CLONING AND FUNCTIONAL-ANALYSIS OF KAPOSIS SARCOMA-ASSOCIATED HERPESVIRUS DNA-POLYMERASE AND ITS PROCESSIVITY FACTOR

Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus 8 , is a newly identified virus with tumorigenic potential. Here, we clo ned and expressed the DNA polymerase (Pol 8) of KSHV and its processiv ity factor (PF-8). Pol-8 bound specifically to PF-8 in vitro, Moreover , the DNA synthesis activity of Pol-8 was shown in vitro to be strongl y dependent on PF-8, Addition of PF-8 to Pol-8 allowed efficient synth esis of fully extended DNA products corresponding to the full-length M 13 template (7,249 nucleotides), whereas Pol-8 alone could incorporate only several nucleotides. The specificity of PF-8 and Pol-8 for each other was demonstrated by their inability to be functionally replaced by the DNA polymerases and processivity factors of herpes simplex viru s 1 and human herpesvirus 6.