Intracellular localization of mouse DNA polymerase-alpha

Proc Natl Acad Sci U S A. 1976 Apr;73(4):1136-9. doi: 10.1073/pnas.73.4.1136.


Although DNA polymerase-alpha (DNA nucleotidyltransferase; deoxynucleoside triphosphate: DNA deoxynucleotidyltransferase; EC probably functions in the nucleus, it is usually found predominantly in the nonnuclear fraction of disrupted cells. We have reexamined the intracellular location of this enzyme using cytochalasin-B-induced enucleation, a technique which avoids exposure of nuclei to extra-cellular conditions during cell fractionation. In conditions where viability of separated cell parts is high and recovery is quantitative, we find greater than 85% of total DNA polymerase-alpha (and DNA polymerase-beta) activity in the nucleated cell fragments (karyoplasts), from which we conclude that the location in vivo of DNA polymerase-alpha is either nuclear or perinuclear. On the other hand, thymidine kinase (ATP: thymidine 5'-phosphotransferase, EC is found primarily in the enucleated cell fragments (cytoplasts). The enucleation procedure used in this work should be of general use for intracellular location studies.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Fractionation
  • Cell Line
  • Cell Nucleus / enzymology*
  • Chromatin / enzymology
  • Cytochalasin B / pharmacology
  • Cytoplasm / enzymology*
  • DNA Nucleotidyltransferases / metabolism*
  • Thymidine Kinase / metabolism


  • Chromatin
  • Cytochalasin B
  • Thymidine Kinase
  • DNA Nucleotidyltransferases