Differential Extraction of DNA Polymerase from the Nucleus of the Mouse Myeloma Cell

• Published in: Cell Structure and Function Vol. 4; no. 4; pp. 295 - 306
• Main Authors: Matsukage, Akio, Nishioka, Nobuyuki, Nishizawa, Miwako, Takahashi, Taijo
• Format: Journal Article
• Language: English
• Published: Saitama Japan Society for Cell Biology 01.01.1979; Japan Science and Technology Agency
• ISSN: 0386-7196; 1347-3700
• DOI: 10.1247/csf.4.295

Eighty four precent of the total extractable DNA polymerasea α activity was associated with nuclei isolated from mouse myeloma MOPC 104E cells in the presence of Ca2+. From the nuclei, DNA polymerase α was extracted from these nuclei in the three separate steps : activity I, KCl free medium (minus Ca2+); II, 100 mM KCl; III, 200 mM KCl. Partially purified DNA polymerase a was eluted from a native or denatured DNA-cellulose colu-mn by 100 mM KCl. This conforms very well to the KCl concentration requiredto extract activity II from nuclei. Therefore, activity II is thought to be bound to the DNA in the nucleus. By contrast the activity I may be in a free form.After extraction, activity III was eluted from DNA-cellulose by the same KCl concentration as were I or II. This indicates that activity III did not have astronger binding ability than I or II to DNA. Activity III may be present in nucleus by binding to specific sites of DNA or its making a complex with somefactor(s). The KCl concentrations required to extract DNA polymerase β and γ conformed to those required to elute these enzymes from a DNA-cellulosecolumn. This evidence suggests that most DNA polymerase β and nuclear DNA polymerase γ made a complex with the DNA in nuclei. DNA polymerase α was resolved into three active forms, A, B and C in the order of their elution from DEAE-cellulose as described previously (13, 21).The activity I described above was composed mainly of form C while the majoractivity of II and III was form B. The DNA polymerase α present in the cytoplasm soluble fraction contained forms A and C. Thus, form B of apolymerase forms a complex with some nuclear structure, presumably DNA, and probably is an active form involved in DNA synthesis.