Incorporation of [³H]Thymidine into Nuclear and Mitochondrial DNA in Synchronized Mammalian Cells

This is the authors' abstract. We don't add key points for this paper.

Human liver cells (Chang) were synchronized by cold shock. The second generation was scanned with two‐hour pulses of [ 3 H]thymidine. The incorporation of [ 3 H]thymidine into nuclear and mitochondrial DNA during each pulse was determined. Maximal incorporation into the nuclear DNA occurred during S‐phase (6 hours long) and to a smaller extent during and shortly after cytokinesis. The mitochondrial DNA was most highly labeled between S‐phase and cytokinesis. The nuclear DNA's had a buoyant density in caesium chloride of 1.699 g/ml, whereas the mitochondrial DNA banded at a density of 1.688 g/ml.