NUCLEIC ACID SYNTHESIS IN TYPES 4 AND 5 ADENOVIRUS-INFECTED HELA CELLS

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Abstract
Type 4 adenovirus infection of HeLa cells effected a marked increase in synthesis of the saline-soluble deoxyribonucleic acid (DNA) fraction, but not the host-cell DNA (the water-soluble fraction). This was demonstrated by the marked increase in specific activity of saline-soluble DNA but not water-soluble DNA when p32-inorganic phosphate or sodium formate-C14 was employed. When these isotopes were used to label cells before viral infection rather than during the process of viral propagation, the saline-soluble DNA from infected cells had a specific activity of 10 to 20% less than that of uninfected cells, indicating that the saline-soluble DNA was synthesized both from prelabeled precursors of the cell pools and unlabeled materials from the medium. Saline-soluble DNA began to increase between 10 to 12 hours after viral infection and 3 to 4 hours before appearance of newly propagated infectious virus. The specific activity of the acid-soluble pool of infected cells also increased between 10 to 12 hours after viral inoculation when sodium formate-C14 was used as a radio-isotope. When p32-inorganic phosphate was utilized, the specific activity of infected-cell RNA was increased approximately the same relative amount as when total RNA was determined chemically; i.e., 30 to 40%. With type 5 adenovirus, not only did a 3- to 5-fold increase in saline-soluble DNA occur, but also an increase was measured in specific activity of RNA when P32 inorganic phosphate was used.