Incorporation of Labeled Precursors into Nuclear and Mitochondrial DNA of Cells Grown in Culture

Abstract

Summary

Incorporation of labeled precursor into nuclear and mitochondrial DNA of cells grown in culture has been studied. The patterns of labeling of the nuclear and mitochondrial DNA are different, in that after change of medium, and addition of precursor, the specific activity of the nuclear DNA steadily increases, while the specific activity of the mitochondrial DNA increases and then decreases. Pulse-labeling experiments show that the rate of incorporation of precursor decreases with time. However, the decline in specific activity with time after addition of medium and precursor, cannot be attributed to degradation of newly formed DNA, which was shown to be stable in the presence of actinomycin D.