Intracellular localization of mouse DNA polymerase-alpha.
Although DNA polymerase-alpha (DNA nucleotidyltransferase; deoxynucleoside triphosphate: DNA deoxynucleotidyltransferase; EC 2.7.7.7) 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 5.7.1.75) 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.
D002458:Cell Fractionation; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology*; D002843:Chromatin / Q000201:enzymology; D003571:Cytochalasin B / Q000494:pharmacology; D003593:Cytoplasm / Q000201:enzymology*; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D013937:Thymidine Kinase / Q000378:metabolism
D002843:Chromatin; D003571:Cytochalasin B; D013937:Thymidine Kinase; D004254:DNA Nucleotidyltransferases