SEA URCHIN NUCLEAR DNA POLYMERASE .2. CHANGING LOCALIZATION DURING EARLY DEVELOPMENT

In sea urchin embryos, there is little change in the total DNA polymerase activity during early development. However, there is a progressive increase in the per cent of this activity which is associated with the nuclear fraction and at the same stage there is a decrease in the amount of activity in the soluble cytoplasmic fraction. By the hatching stage (about 300 cells/embryo) most of the DNA polymerase activity is found in the nucleus. The intracellular migration of polymerase from the cytoplasm to the nucleus is suggested as a mechanism to account for these results. © 1969.