Murine DNA Polymerases I. Distinguishing Characteristics of Two Activities Separated by Phosphocellulose Chromatography

Abstract

Summary

Murine DNA polymerases C, A, and N have been separated on phosphocellulose columns. Polymerase C is preferentially stimulated by “activated” DNA, and polymerase N is preferentially stimulated by poly rA · poly dT. The template preferences of polymerases C (“activated” DNA) and N (poly rA poly dT) recovered from phosphocellulose columns were retained regardless of salt concentration and were not due to contaminating nucleases in the column fractions. The optimal salt and pH, as well as synthetic template preferences, of peaks I and III recovered from phosphocellulose firmly identify them as polymerase C and polymerase N, respectively, The number of polymerases and the identity of polymerase activities in peak II has not been resolved, but the presence of polymerase activity stimulated by poly rA-dT_12-18 is suggestive of an RNA-directed DNA polymerase.