Synthesis of cellular and viral macromolecules under conditions of suboptimal temperature

Summary

The synthesis of RNA and proteins in HeLa cells, as well as the synthesis of RNA and proteins of poliovirus in these cells incubated at 23°C were studied. The synthesis of cellular RNA at 23°C was about 10% of that at 36°C, the synthesis of high-molecular fractions of RNA being inhibited at 23°C to a greater extent than that of low-molecular fractions. At 23°C the total synthesis of cellular proteins only measured about 30% of that found at 36°C. Results obtained after addition of actinomycin D or cycloheximide to the system suggested that RNA synthesized at 23°C possessed matrix activity and that proteins formed at this temperature, could participate in RNA synthesis.

Though synthesis of viral RNA could not be demonstrated in HeLa cells incubated at 23°C, poliovirus inhibited the synthesis of cellular RNA and proteins. However, proteins capable of reacting with virus specific antiserum in the immunofluorescence test were formed. In contrast to observations at optimal temperature, inhibition of synthesis of both cellular macromolecules and viral antigen was reduced (approximately 20-fold) at 23°C. The virus-induced RNA-polymerase synthesized at 36°C was capable of functioningin vivo at 23°C to a considerable extent.