Temperature-Sensitive DNA Polymerase from Rous Sarcoma Virus Mutants

Abstract

The DNA polymerase which can be isolated from the virions of RNA tumor viruses (the “reverse transcriptase”) has many properties which suggest that its role is to synthesize a DNA copy of the viral RNA genome (Temin and Baltimore, 1972). Only genetic experiments, however, are able to definitely establish whether it does act to copy the viral genome. Recently, Linial and Mason (1973) and Wyke (1973) have isolated and characterized temperature-sensitive mutants of Rous sarcoma virus which show temperature-sensitive synthesis of DNA in vitro. These are mutants in a function necessary only very early in the viral growth cycle. It therefore seems likely that these mutants represent temperature-sensitive DNA polymerase mutants and could be utilized to delineate the function of the DNA polymerase found in the virions of RNA tumor viruses.