BIOCHEMICAL STUDIES ON ADENOVIRUS MULTIPLICATION .14. MACROMOLECULE AND ENZYME SYNTHESIS IN CELLS REPLICATING ONCOGENIC AND NONONCOGENIC HUMAN ADENOVIRUS

Exponentially growing KB cells infected with nononcogenic Ad 2 and oncogenic Ad 12 and 31 stopped dividing but continued to synthesize and accumulate protein, DNA, and RNA. The protein and DNA content per infected cell was twice that of uninfected cells at 36 hours after infection and the RNA content increased by 30-80% until 20 hours after infection and then sharply decreased to the initial levels. The rate of synthesis of protein, DNA, and RNA per cell increased initially and then decreased in cells infected with Ad 2, 12, and 31 as determined by pulse labeling with radioactive valine, thymidine, and uridine. Stimulation and inhibition occurred later after infection with oncogenic adenoviruses. Infected cells incorporated two to three times more valine, thymidine, and uridine into the acid-soluble fraction than did uninfected cells. The species of DNA synthesized at different times after infection were identified by density gradient centrifugation and by DNA-DNA hybridization. Host cell DNA synthesis was blocked completely at 24 to 36 hours after infection with Ad 2, 7, 12, 18, and 31. DNA polymerase activity did not increase after infection of exponentially growing KB cells with Ad 2, 12, or 31. Thymidine kinase activity was increased 2- to 3-fold in cells infected with Ad 12 and 31, but not in cells infected with Ad 2. Stimulation of enzyme activity in adenovirus-infected cells may depend upon the base level of enzyme activity in the uninfected host cell and the growth rate of the virus. © 1969.