The RNA and DNA contents of the nucleus and cytoplasm of the HeLa cell were determined. The rates of incorporation of P32 into the various nucleic acid fractions were established for the ordinary HeLa cell maintained under a set of standard conditions.
The changes in the rates of incorporation of P32 and in the amounts of RNA and DNA which occurred subsequent to infection with poliovirus were followed throughout the infectious cycle. These changes were correlated with the intracellular appearance of the newly formed virus. A net synthesis of RNA occurred in the cytoplasmic component of the cell. The increase was detectable 2 hours before the first appearance of demonstrable virus and reached a maximum (2.5 times normal) at 6 hours. Viral increase was not maximal before the 7th hour after infection.