Purification and characterization of mouse DNA polymerase α devoid of primase activity

Abstract

A simple method was developed for the isolation of primase-free DNA polymerase-α from the DNA polymerase-α-primase complex of mouse FM3A cells. The polymerase was separated from primase submits by chromatography on a single-stranded DNA-cellulose column in the presence of 50% etylene glycol. The primase-free DNA polymerase-α contained two polypeptides with molecular masses of 180000 and 68000. Analysis of the DNA products with poly(dA)-oligo(dT)10 as template-primer revealed that both primase-free DNA polymerase-α and the DNA polymerase-α-primase complex predominantly synthesized short DNA with less than 30 nucleotides, but that the DNA polymerase-α-primase complex also synthesized some longer DNA with more than 300–400 nucleotides.