RNA synthesis in Chinese hamster cells. II. Increase in rate of RNA synthesis during G1.

Cultures of mitotic Chinese hamster cells, prepared by mechanical selection, were pulse-labeled with methionine-methyl-(14)C or with uridine-(3)H at different stages in the life cycle. The rate of (14)C incorporation into 18S RNA was measured, as was the rate of uridine-(3)H incorporation into total RNA for both monolayer and suspension cultures. The rate of incorporation increased continuously throughout interphase in a fashion inconsistent with a gene-dosage effect upon RNA synthesis.