On the Binding of DNA Polymerase Alpha to Nuclear Structure in Mouse Myeloma MOPC104E

Abstract

DNA polymerase α of mouse myeloma MOPC104E cells was resolved into at least three active types which were designated forms A, B and C in order of elution from DEAE cellulose column. Eighty-four percent of total DNA polymerase α activity of mouse myeloma MOPC104E cells was found localized in nuclei isolated using Ca2+-containing medium. Forty percent of total nuclear activity was released upon treatment with salt-free medium, and most of the remaining activity was extracted with media containing 0.15 or 0.3 M KCl. The major species of 0 M KC1 extract was form C of DNA polymerase α, while the activity in 0.15 M KC1 extract was mainly composed of form B. The KC1 concentration required for extraction of form B from the nuclei seemed to coincide with that required for the elution of DNA polymerase α from native DNA cellulose column. These observations suggest that form B is in the complex with DNA or chromatin structure in nucleus whereas form C is free from the structure.