Induction of Cellular Deoxyribonuleic Acid Synthesis by Simian Virus 40

Abstract

The incorporation of 3 H-thymidine ( 3 H-dT) into deoxyribonucleic acid (DNA) has been studied in uninfected confluent monolayer cultures of monkey kidney and mouse kidney cells, simian virus 40 (SV40)-infected cells, and in SV40-transformed mouse kidney cells. Radioautographic measurements revealed that during the period from 28 to 51 hr after productive SV40 infection of monkey kidney cultures about 80% of the cells synthesized DNA, compared to about 16% in uninfected cultures. At 28 to 43 hr after abortive SV40 infection of mouse kidney cultures, 24 to 37% of the cells synthesized DNA, compared to about 6 to 8% in uninfected cultures. The infected monkey kidney and mouse kidney cultures, respectively, incorporated about 5 to 10 times and 3 to 5 times as much 3 H-dT into DNA as did uninfected cultures. Moreover, the net DNA synthesized by SV40-infected monkey kidney cultures, estimated by colorimetric methods, substantially exceeded that of uninfected cultures. Nitrocellulose chromatography and band centrifugation experiments were performed to elucidate the kinds of DNA synthesized in the cultures. In uninfected monkey kidney cultures and at 2 to 12 hr after SV40 infection, almost all of the 3 H-dT labeled DNA sedimented more rapidly than SV40 DNA, and the radioactive DNA was denatured by heating for 12 min at 100 C (cellular DNA). Almost all of the labeled DNA obtained from abortively infected mouse kidney cultures and from SV40-transformed cells also had the properties of cellular DNA. However, approximately one-third to one-half of the labeled DNA obtained from monkey kidney cultures 28 to 51 hr after infection sedimented more slowly than cellular DNA and was not denatured by the heating (SV40 DNA). It is concluded that cellular DNA synthesis was induced during either the productive or abortive SV40 infections.

Deoxyribonucleic Acid Replication in Simian Virus 40-Infected Cells

“…Viral DNA synthesis in BSC-1 cells was first observed at 30 to 38 hr after infection. These results are in agreement with previously published reports (6, 13,15). of 1.95-fold.…”

“…3). The kinetics of induction of cellular DNA synthesis in AGMK and CV-1 cells were similar and in good agreement with published results from other laboraties (9,13,22,23). Induction of cellular DNA in these cells began at about the same time as viral DNA synthesis.…”

“…On the other hand, no induction of cellular DNA synthesis was detected in BSC-1 cells. These data are in good agreement with previously published reports (6,9,13,22,23). Between 13 and 23% of the AGMK cell DNA was found to be excised to small molecular weight fragments by 96 hr after infection.…”

“…The different responses of these three cell lines during SV40 lytic infection may help unravel some of the B 312 316 40 44 mechanisms involved in induction and excision R of cellular DNA. SV40 lytic infection of AGMK and CV-1 cells, oK cAeMKlcdDNA but not BSC-1 cells, results in the induction nh 3H-thAmGdMK el of cellular DNA synthesis (6,9,13,22,23).…”

Infection and Transformation of Mouse Peritoneal Macrophages by Simian Virus 40

“…No newly synthesized SV40 DNA could be detected under conditions in which about 95-97 % of the marker SV40 DNA could be recovered in the supernatant fraction. Thus, it appears that mouse peritoneal macrophages, like other mouse cells (17), are essentially nonpermissive for SV40.…”