Abstract
1. The changes in the metabolism of phosphorus compounds of vaccinia virusinfected HeLa cells were investigated by the incorporation of radiophosphorus and tritiated thymidine.
2. HeLa cells were cultured with the radioisotopes in monolayer or in suspension under magnetic stirring after the virus infection.
3. In comparison with normal HeLa cells, vaccinia virus-infected HeLa cells showed an increased incorporation of radiophosphorus into acid-soluble and phospholipid fractions 2-4 hours after the infection, and the incorporation into RNA fraction became higher 4-7 hours after the infection, followed by an elevated incorporation into DNA fraction with a concomitant decrease in RNA fraction.
The final incorporation of radiophos-phorus into DNA fraction of the infected cells was lower than that of the non-infected one after 21 hours.
4. The incorporation of tritiated thymi-dine into DNA fraction was similar to that of radiophosphorus, but the increased incorpo-ration of the tritiated thymidine began earlier than that of radiophosphorus.
5. The incorporation of radiophosphorus into individual nucleotides in acid-soluble fraction 4 hours after the infection showed no marked difference from the control except the decrease of incorporation into ATP fraction in contrast to the increase of that into inorganic orthophosphate fraction, and no peculiar nucleotides was found to appear or disappear in response to virus infection.
6. Possible role of acid-soluble fraction and RNA in biosynthesis of DNA virus is discussed.
We wish to express our thanks to Dr. I. Tagaya, head of the Division of Enterovirused, the National Institute of Health, Tokyo, and to Prof. Dr. H. Yoshikawa, the Department of Nutrition and physiological Chemistry, Faculty of Medicine, the University of Tokyo, Tokyo.
