RNA‐Dependent DNA Polymerase from a Cell Line Derived from the Bone Marrow of a Patient with Polycythemia vera

Abstract

A RNA‐dependent DNA polymerase was isolated from a human cell line derived from the bone marrow of a patient with polycythemia vera. The purification procedure included chromatography on phosphocellulose and oligo(dT)‐cellulose, and glycerol gradient centrifugation. The enzyme could be distinguished from polymerase A by salt elution from phosphocellulose, utilization of poly(rC) · oligo(dG) and its molecular size of about 70 000, as determined by centrifugation. Throughout the purification procedure ribonuclease H activity was co‐purified. Upon dodecyl‐sulfate‐polyacrylamide electrophoresis on microgradient gels two main bands with molecular weights of 68 000 and 66 000 and three minor bands were detected. The enzyme preferentially used poly(rA) · oligo(dT) as template‐primer compared with poly‐(dA) · oligo(dT). It incorporated dGMP into polymer on poly(rC) · oligo(dG).