Temporal Coordination of DNA Replication with Enzyme Synthesis in Diploid and Heteroploid Cells

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Science  19 Dec 1969:
Vol. 166, Issue 3912, pp. 1536-1538
DOI: 10.1126/science.166.3912.1536


The rate of DNA synthesis in the S phase of growth of synchronized diploid Chinese hamster cells shows two maximums, while in heteroploid hamster cells the DNA replication rate is constant. In diploid cells a reciprocal relationship exists between maximum DNA synthetic rates and maximum lactate dyhydrogenase and thymidine kinase enzyme levels. Enzyme activity in heteroploid cells increases continuously through the cell cycle with no evidence of oscillations. It seems possible that these differences in molecular organization may accompany or precede the transition to heteroploidy.

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